Internet Surfer 2.0/Internet Surfer 2.0 (Wayzata Technology) (1996).iso/pc/text/mac/faqs.435

Text File | 1996-02-12 | 29KB | 571 lines

Frequently Asked Questions (FAQS);faqs.435



That's about it for the "general etiquette" information.  General pictures
information is continued in part 2 of this FAQ.  If you have any
suggestions for things to include in future versions, don't hesitate
to let me know...

         ~ deej ~              | (If I were expressing Cadence's opinions, )
Jim Howard -- [e-mail] | (they'd probably make me wear a tie...    )
        (^:=             Flames cheerfully ignored.             =:^)
"I tell you this:  no eternal reward will forgive us now
 for wasting the dawn" -- Jim Morrison, The Doors
Xref: bloom-picayune.mit.edu alt.binaries.pictures.d:6168 alt.binaries.pictures.utilities:1494 alt.binaries.pictures.fractals:690 alt.binaries.pictures.fine-art.d:53 news.answers:4585
Path: bloom-picayune.mit.edu!enterpoop.mit.edu!biosci!uwm.edu!cs.utexas.edu!sdd.hp.com!saimiri.primate.wisc.edu!caen!uunet!Cadence.COM!deej
From: [e-mail] (Jim Howard)
Newsgroups: alt.binaries.pictures.d,alt.binaries.pictures,alt.binaries.pictures.utilities,alt.binaries.pictures.fractals,alt.binaries.pictures.fine-art.d,news.answers
Subject: alt.binaries.pictures FAQ - General info
Message-ID: <[e-mail]>
Date: 14 Dec 92 09:23:04 GMT
Expires: Mon, 11 Jan 1993 00:00:00 GMT
References: <[e-mail]>
Sender: [e-mail] (Usenet News)
Followup-To: alt.binaries.pictures.d
Organization: Cadence Design Systems, Inc.
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Approved: [e-mail]
Supersedes: <[e-mail]>
Nntp-Posting-Host: cds8613.cadence.com

Archive-name: pictures-faq/part2
Last-modified: 13 November 1992

    This is part 2 of the FAQ for the alt.binaries.pictures* hierarchy.
    This part of the alt.binaries.pictures FAQ contains "general", or
    operating-system independent information.  It answers (hopefully) all
    the questions you may have about the pictures newsgroups, decoding and
    encoding techniques, and picture formats.

      For information on issues of etiquette and posting policy and/or
    suggestions, consult part 1 of this posting.

      For information on your particular system and on specific utilities,
    consult part 3 of this posting.

    Before posting to these groups for the first time, please check the FAQ
    list (this posting - including parts 2 and 3), and also read the newsgroup
    news.announce.newusers, which contains many answers to questions about
    UseNet in general.

    If you've read previous versions of this FAQ, you'll probably only want
    to read anything that has changed since the last distribution.  These
    changes appear both in this document and in the accompanying "Changes to
    the alt.binaries.pictures FAQ".  Note that this is a "live" document, and
    is always getting important information added or updated.


***********************************************************************

This file is intended to be a general introduction to the pictures
newsgroups, answering some common questions concerning pictures posted
in those newsgroups, namely how to decode and view them.  It is not, of
course, possible to cover everything, but I will try to to get as much
as I can into this file.  If you feel something important has been
omitted and you know the subject well, please write me so I can
include the info for future releases.  E-mail should be sent to
[e-mail] for these purposes.

Before you miss an important detail contained in this file, let me
"pre-repeat" that many of the programs mentioned in this document are
available for anonymous ftp at bongo.cc.utexas.edu (128.83.186.13), in
the gifstuff directory.  Also: there are NO GIF files of any kind at
this site!  Save your time and don't bother looking for them!

Articles contained in the news groups in the alt.binaries.pictures*
hierarchy are available ONLY by subscribing to those groups through UseNet;
there are no FTP archive sites (with the exception of a.b.p.fractals - see
the "ftpsites" list on bongo), mailing list, or mail servers that allow
access to these articles.  If you want access to the pictures hierarchy, your
site must subscribe to it;  talk to your news administrator!
Alternatively, you might be able to access these groups by connecting to
another site that *does* carry them, and do your news reading there (then FTP
the articles back to your site).  This may also be a problem, as you may not
be able to telnet to another site (because you don't have a true Internet
connection), and you might also not be able to access news at that site
without the OK of the systems administrator.  You might check out either the
alt.internet.access.wanted or the alt.internet.services news groups to get
more info or make requests for remote access...

OK... on to the real reason you're reading this document...


TABLE OF CONTENTS
   I.   ABOUT THIS FAQ
  II.    DOWNLOADING AND DECODING FILES
 III.   COMMON PICTURE TYPES
  IV.   ENCODING AND UPLOADING FILES
   V.   ALTERNATE SOURCES FOR PICTURES/HOW-TO'S OF FTP
  VI.    COMMON PROBLEMS
 VII.   COPYRIGHT


I. ABOUT THIS FAQ

This FAQ is posted every other Monday to the alt.binaries.pictures
newsgroups and to news.answers.  It is also available by anonymous FTP,
from UUCP, or through e-mail by using the services available from a couple
of mail servers.  For anonymous FTP access, you can look on either
pit-manager.mit.edu [18.72.1.58] in the directory /pub/usenet/news.answers,
on ftp.cs.ruu.nl [131.211.80.17] in directory NEWS.ANSWERS, on
cnam.cnam.fr [192.33.159.6] in directory /pub/FAQ, or on ftp.uu.net
[137.39.1.2, 137.39.1.9, or 192.48.96.2] in directory /pub/usenet.  In all
cases, you'll want to get one or all of the FAQ parts named as files
"pictures-faq/part1", "pictures-faq/part2", and "pictures-faq/part3".
You can get the FAQ via UUCP by retrieving the appropriate part from
"uunet!/archive/usenet/news.answers/pictures-faq/part1",
"uunet!/archive/usenet/news.answers/pictures-faq/part2", or
"uunet!/archive/usenet/news.answers/pictures-faq/part3".
    For e-mail access, send a message to [e-mail]
with the mail body "send usenet/news.answers/pictures-faq/part1" to get the
first part, "send usenet/news.answers/pictures-faq/part2" for the second,
and "send usenet/news.answers/pictures-faq/part3" for the third, or e-mail
to [e-mail] with "send NEWS.ANSWERS/pictures-faq/part1",
"send NEWS.ANSWERS/pictures-faq/part2", and/or
"send NEWS.ANSWERS/pictures-faq/part3" in the body of the message.


II. DOWNLOADING AND DECODING FILES

    Basic checklist:        Alternate checklist:
    ----------------        --------------------
    News reader            News reader (optional in some cases)
    Text file editor        "Super-decoder"
    UUDECODEr

By far the most common method of posting files to the pictures
newsgroups is the UUENCODE standard.  This program, shipped standard
with most implementations of UNIX, converts binary files into plain-text
ASCII files which can be handled by the mail system.  You will need a
version of UUDECODE before anything else in order to view anything
downloaded from the net.  If your system does not have a version of
UUDECODE available, you can get one via anonymous ftp from
bongo.cc.utexas.edu, in the gifstuff/uutools directory.

The format of a uuencoded file consists of an optional "table specification",
which consists of the word "table" alone on a line, followed by one or more
lines containing the characters that will be used in the remaining encoded
data.  Following this, the standard requires the line containing only the text
"begin <permissions> <filename>" (where "<permissions>" is a three-character
numeric string, and "<filename>" notes the name of the decoded file - for
example "begin 640 myfile.gif").  This "begin" line is then followed by
several lines of approximately 63 characters, all beginning with a capital
"M", and containing any non-lower-case printing character (and very rarely
resembles anything but absolute gibberish).  Optionally, one to two lines
may be blank or contain less than the normal number of characters if those
lines are immediately before the line containing the "end" notation.  The
"end" text alone on a line marks the conclusion of the uuencoded data.  Any
information that does not fit into the above classifications are termed as
either "headers" or "trailers", and are not intended to be included in the
information to be decoded.  For example, the following represents a valid
uuencoded file (although it contains no useful information - don't bother
decoding it!):

begin 666 bogus.file
MLEHHWHURHUH %$^4653%#$#&^%$$46^%#^%)LKDUHEWFHIUG^$^#DJIUTE&F^R
M&#H:FNP(ENER(*HNFUHDG(&#&B#HY@#(*@YNUF(&$HU$HF(YSAUHIRY(&YHHEU
M(*NUFE(YHDH

end

Most decoders are smart enough to ignore anything before the "begin" line
and after the "end" line.

The first step is to save the file you want to view... in most versions
of the newsreader, this is done by pressing 's' followed immediately (no
spaces usually, although some versions don't care) by a file name.
You will usually be asked if you want to save it in mailbox format;
you should answer 'n'.  When saving an article to a file in
mailbox format, the article is sometimes changed in a subtle
way, making it impossible to decode.

In the case of a single-part file, you can now uudecode the file,
which will create whatever output file is encoded.  You can usually
tell if it's a single-part file by looking on the subject line;
standard netiquette is to make something like [03/06] part of the
subject line, which indicates you're on part 3 of a 6-part file.  If no
numbers are there, you can usually assume it is a 1-part file.  If
not, feel free to write the poster (directly... please don't waste
bandwidth by posting) and request that he/she put this info in the
subject line.  Be nice about it!  Another way to determine if a file
is a single-parter is if both the uuencode "begin" and "end" lines
(as outlined above in the description of the uuencode format) are
included in the file.

For multi-part files, life is a little more difficult.  If all you
have is a standard UUDECODE program (as opposed to a "smart decoder"),
you will need to trim the headers and trailers out from the rest of the
information.  You can either do this by saving each part in its own file
and editting them separately, then concatenate the editted files together
to make one big file (this might be your only choice if your editor can't
handle large files!), or you can save each part in order into one big
file and then edit all the headers and trailers out from that file.
Either way, you'll need to run the result through UUDECODE.  You can use
your favorite text editor to strip out header and trailer information.

There are several "smart decoders" out there that will handle all of
the header/trailer stripping and decoding for you (some will even make
sure that the pieces are in order!) - see part 3 of this posting for
specifics.

Some articles are actually posted with easy decoding in mind, and contain
UNIX shell script headers/trailers that facilitate easier decoding.  This
is often very helpful, as it saves you a lot of work, and can also provide
error checking not available in a "normal" uuencoded posting.  These
postings nearly always contain instructions on their use, so I won't
attempt to explain all the details here.  There's no set "standard" for
this type of posting anyway - except for MIME.  MIME, the Multipurpose
Internet Mail Extensions, proposes a standard for the posting and mailing
of multi-media articles (postings may include pictures, sounds, movies,
or other media types - which may be combined in one article).  Public-
domain packages using MIME are available (Metamail, for example).  For
more information on MIME and Metamail, contact [e-mail].

Some news readers have an "extract" capability that greatly simplifies
life by automatically decoding articles - this means you don't have to
go to the hassle of saving to a file and then decoding.  Newer versions
of rn, nn, and trn can handle this - check the "man" page or ask your
news administrator to find out if you can let your news reader do the
work for you!

If you're going to download the decoded picture file to a home machine,
or move it around a network, remember that most decoded file outputs are
going to be BINARY files, so set your transfer protocol accordingly.
If you are moving around just the uuencoded data, an ASCII transfer will
work just fine, however (you'll have to decode it eventually, of course).
Note that if you *don't* transfer the decoded file in BINARY mode,
everything will appear to work just fine - until you try to view the
picture.  Then you'll get all sorts of undefined results...


III.  COMMON PICTURE TYPES

    Basic checklist:        Alternate checklist:
    ----------------        --------------------
    GIF viewer            Multi-format viewer
    Format conversion tool(s)    Format conversion tool(s)
                    Image manipulation tool(s)

OK.  Now you've got this great picture file from downloading it and
running it through UUDECODE.  What is it, and what do you do with it?

The most common type of picture is the GIF format (which usually has
a .GIF or .gif file suffix).  GIF stands for Graphic Interchange Format,
and is a standard format for images that was developed by CompuServe to
be a device-independent method of storing pictures.  It includes
Lempel-Ziv-Welch (LZW) compression, which makes the files fairly small.

JPEG is another standardized image compression mechanism, which stands
for Joint Photographic Experts Group (the original name of the committee
that wrote the standard).  It seems more and more common that JPEG-type
pictures (.JPG or .jpg file suffix, usually) are getting posted to the
net.  Some claim that JPEG is destined to overtake GIF format in popularity,
because it is the most compact method to store 24-bit data, but mostly due
to the fact that it uses much less space to store the same picture (this is,
in fact, true - I have seen many examples of this phenomenon).  This may be
an accurate assessment, but this will probably take a while to happen, as
most people HAVE GIF software/viewers, but lack JPEG equivalents.
Undoubtedly, however, this too shall change, but at this point, JPEG is
recognized as still being in its infancy.  But, if you prefer to be on the
leading (bleeding?) edge, it is possible to get software both to view JPEG
pictures, and to convert JPEG to and from other formats, as detailed in
part 3.

The latest and greatest info about JPEG is included in the Tom Lane's
"JPEG image compression: Frequently Asked Questions" (archive name is
"jpeg-faq"), posted on a regular basis to the alt.binaries.pictures.d,
alt.graphics.pixutils, alt.binaries.pictures.erotica.d, alt.sex.pictures.d,
and news.answers newsgroups.

Of course, to view a picture of a particular type, you will need a viewer
that supports that type (again, for specifics on viewers for your
particular configuration, see part 3 of this posting).

There are other types of single-picture files posted to the net,
although they are not as common as GIF or JPEG files.  Other than the
difference in the viewing software, the downloading/decoding and
encoding/uploading procedures are identical as for other types of pictures.
Platform-dependent picture types and conversion programs are discussed
in part 3 of this posting.

Occasionally people get into an argument about which standard is best.
I think the answer is:  WHO CARES?!?  The only thing I have to say
about this matter is that almost every machine under the sun already
has a program written for it to view GIF files, and if yours doesn't,
shareware or PD source code is available almost everywhere.

Commonly people post files to the net with a .GL extension.  These
files are actually animated picture-shows that can be viewed on a small
number of system types.

Usually, GL files are huge, so people often compress them with one of
several popular compression/archiving packages.  Perhaps the most
common is the PC family's PKZIP package.  If a GL file is posted with
a .ZIP extension, you know it's been ZIP'ed.  Similarly, if it has a
.Z extension, it's been compressed with the UNIX `compress' utility.
"Uncompression" tools of either type are available for various types of
systems - part 3 has the necessary details.

Files of a .DL extension are also sometimes posted.  These are very
similar to GL files, except in format and in the fact that DL files allow
color "movie" viewing, so of course it takes different software to view
them (this software is also discussed in part 3).

Then there's FLI - yet another GL/DL type of file.  FLI's are generally
considered poorer quality than either GL or DL, however.

The table below lists many of the common file types for pictures or
compression formats for different systems.  This information may be useful
if you download a tool and then don't know how to decompress it into a
usable form, or as a "quick reference" of file types.   Decompressors or
viewers of "unlike" system types exist on some systems - see the particular
system information for details on this aspect.

    File extension        File  type
    --------------        ----------
    ARC            ARChive (many OS's support) - compressed file(s)
    ARJ            Yet another archive format - compressed file(s)
    BMP            IBM BitMaP picture file
    CPT            Macintosh CompactPro compressed file.
    DL            Animated picture file (system independent, for
                those with viewers)
    FLI            Animated picture file (system independent, for
                those with viewers)
    GIF            Graphics Interchange Format -
                system independent picture file
    GL            Animated picture file (system independent, for
                those with viewers)
    IMG            IMaGe - ? picture file
    JPG (JPEG)        Joint Photography experts Group - system
                independent picture file
    LZH            Amiga LZH - compressed file(s) - LHarc output
    MAC (MACP)        Macintosh MacPaint - Macintosh picture file
    HQX            Macintosh BinHex - encoded file
    IFF            Amiga Interchangeable File Format - Amiga
                file interchange (used for many types of binary
                data).  If it contains a picture file, then
                the picture is either an ILBM (InterLeaved
                                BitMap), HAM (Hold-And-Modify), DHAM (DynaHAM),
                or SHAM (Sliced HAM).
    IM8 (RAST)        Sun RASTer file - Sun picture file
    PCX            IBM PC Paintbrush - IBM picture file
    PICT            Macintosh QuickDraw PICTure - Macintosh picture
                file
    PS (PSID)        Encapsulated PostScript/PostScript Image Data -
                printer-ready text/picture file
    RAW            RAW RGB - 24-bit system independent picture file
    SEA            Macintosh Self-Extracting Archive
    SHK            Macintosh Shrinkit - compressed file(s)
    SIT            Macintosh StuffIt - compressed file(s)
    TGA            TrueVision TarGA file - ? picture file
    TIFF            Tagged Image Format File - 24-bit system
                independent picture file
    UUE            UNIX UUEncoding - encoded file
    XBM            X windows Bit Map - UNIX/X windows picture file
    Z            UNIX LZW "compress" - compressed file(s)
    ZIP            MS-DOS ZIP - compressed file(s)
    ZOO            MS-DOS ZOO - compressed file(s)


IV. ENCODING AND UPLOADING FILES

    Basic checklist:        Alternate checklist:
    ----------------        --------------------
    UUENCODEr            "Auto-posting" tool(s)
    Editor or file splitter
    News posting software

First things first:  before you do any sort of posting, be sure you've
read and understand the a.b.p* netiquette as outlined in part 1 of this
FAQ.  This will save you from countless flamings!

OK.  You need to UUENCODE the file.  Find an encoder and encode it!
If the output file is particularly large (i.e. more than 60 KB), it
would be wise to split up the encoded file into smaller parts (<= 60 KB)
and then post those.  You can split the file with a text editor if you
like, or check part 3 for more specifics on splitting utilities.

Now post the files... and remember to include the neat info mentioned
in part 1, like subject lines that mean something, descriptions,
checksums, "Cut Here" lines, etc...

There are some very nice "super posting" utilities out there that will
handle all the lower-level details for you.  See part 3 for more info
on these utilities.  If you don't use one, you'll obviously need to do
all the uuencoding, splitting, and the posting of each split part
yourself - which can become quite a tedious process!  Another benefit of
the "super posters" is that they enforce some standardization on the way
posts look - making an auto-decoder's job much easier in the process!


V. ALTERNATE SOURCES FOR PICTURES/HOW-TO'S OF FTP

    Basic checklist:        Alternate checklist:
    ----------------        --------------------
    Direct Internet access        E-mail software
    FTP software

The pictures newsgroups are certainly not the only source for pictures,
nor are GIF files the only types available (see section III).  The most
likely place you are to find other pictures is in an archive that is
reachable via FTP.  FTP stands for File Transfer Protocol, and is a
program for transmitting files over the network.  To use FTP, you will
need access to a computer with the FTP program, and a network connection.
Be aware that files on FTP sites will probably NOT be UUENCODED, so
remember to transfer in binary when getting non-text files.
For the greatest level of detail on FTP, you should refer to the posting
"How to find sources (READ THIS BEFORE POSTING)", which is periodically
posted to comp.sources.wanted, alt.sources.wanted, and news.answers.  OR
you can execute either 'finger [e-mail]' or
'finger [e-mail]' to get a quick tutorial.
Additionally, it is possible to get files from anonymous FTP sites via
e-mail.  For details on this wonderful facility, send an e-mail containing
the text "help" to [e-mail].  For those of you on BITNET,
send an e-mail containing the text "help" to [e-mail].
Now you too can get all sorts of great utilities from anonymous FTP sites
using an e-mail proxy!

Due to popular demand, an anonymous FTP site list of pictures-related
"stuff" has now been compiled and is available from bongo in
/gifstuff/ftpsites.  This list is by no means guaranteed to be accurate
or comprehensive, but hopefully most of the information is valid.  BTW,
this list is a condensed and supplemented version of the Jan. 20, 1990
revision of Jon Granrose's ([e-mail]) "List of Hosts that
Accept Anonymous FTP Requests", which is posted regularly to comp.misc,
comp.sources.wanted, and alt.sources.wanted, and also available via
anonymous FTP from pilot.njin.net (128.6.7.38).  Any additions or
corrections would be most welcome and appreciated!

Most ftp programs will allow you to enter something like
  ftp wsmr-simtel20.army.mil
which will connect you with the mighty SIMTEL-20 archives at the White
Sands Missile Range.  Occasionally, you will encounter an ftp program
that is old enough or slothful enough that it does not recognize
internet-style addresses like the one above.  In that case, you'll
need to know the computer's numeric address; for SIMTEL-20
you would enter
  ftp 192.88.110.20

Once you're connected, you'll have to tell the computer at the other
end that you want to log in, by entering USER (some machines save you
this step by *assuming* you want to log in.  What else would you want
to do?)  When you are prompted for an account name, enter
  anonymous
When it asks you for a password, enter *your* internet address.

Often the machine to which you are trying to connect will be busy
(i.e. too many anonymous users), in which case the machine will inform
you of this and throw you off.  Try again later.

Now you're in.  What do you do?  Well, you need to know where the
files are stored that you want.  If you know this, just
  cd directory-name
to the directory in question.  Then you can do a DIR to find out
what is in it.

So you see a file called CRSH+BRN.GIF and you want it for yourself.
What do you do?  Well, the first thing is to tell the computer on the
other end that you want it to transmit a binary file.  On most FTP
servers, entering the magic word TENEX will do this.  If the machine
doesn't recognize TENEX, try BINARY, or if all else fails, you can
enter
  TYPE L 8
Be sure to do this for GIF files or you'll get garbage when you try
to view them!
The difference between TENEX and BINARY is in translation of data type
sizes - if your machine type has different data type sizes than the one
you're downloading from, use TENEX, otherwise use BINARY.  If you're not
sure, try TENEX first (if the command isn't recognized, you're probably
OK).  On some VAX platforms, the keyword "IMAGE" is also sometimes used
to denote binary files.

Now you're ready to grab the files you want.  You have two options:
you can type
  get filename
or
  mget wildcard
where wildcard is any UNIX-style wildcard.  MGET will get all files
that satisfy the specification.

When you're done grabbing files, type QUIT or BYE to log off the remote
machine and return to yours.  Now you're ready to view the picture -
no decoding step necessary (neat, eh?)!

Most of the non-erotica pictures that appear in postings to the
alt.binaries.pictures* hierarchy are available from anonymous FTP sites
(again, see bongo's "ftpsites" list), but this is of course not guaranteed.

The other most common method for obtaining files is from an archival
file server.  Most of these work in the following way: you send mail
to the server's address, with one-line commands in your message, like
   help
   directory \pictures\gif\family-oriented
   send \pictures\gif\family-oriented\CRSH+BRN.GIF
and the requested info is sent back to you at some later time, when
the server has time to get around to it.

The first step when you discover a server system is to send a HELP
command so you can learn what the commands are for that server.
However, most servers operate with commands basically similar to those
listed above.


VI. COMMON PROBLEMS

    Basic checklist:
    ----------------
    At least one clue
    Some small level of intelligence
    Self-determination

Well, you've downloaded the file, tried to view it, and got garbage.
What went wrong?

The two most likely places for something to go wrong are both in the
transmission of the file.  The first is this:  when you downloaded the
file to your home computer, did you remember to tell the modem-
transfer software that you're sending a binary file?

The second-most likely is that you forgot to say TENEX before you
grabbed the file via FTP.

Either of these will result in mangled files that are unviewable by
anything known to man.

Also: did you remember to trim off the header and trailer information if
you are/were using a "simple" uudecoder?  The symptom of forgetting to
do this is usually a message something like "short file" from your GIF
viewer.  There could also be the problem where blank lines are left
between parts (or anywhere for that matter) within the 'begin' and 'end'
lines of the uuencoded file.  Uudecode will get through them fine, but some
GIF viewers will choke on the results.  The only blank line I've seen
get by is the one just before the 'end' statement.  Beware of taking
too much or not enough off of the headers and trailers.

Another common problem is this one:  IBM mainframes often use an
EBCDIC character set (yes, there's more than one EBCDIC set!) instead
of the ASCII set used by everyone else.  This wouldn't be a problem except
that most ASCII-EBCDIC converters have a bug which mungs the translation
of several characters, including ^ { } and a few others.  Even this
wouldn't be a problem except that the particular munging it does is to
map several of these characters onto the *same* wrong character.  Ooops.

The way around this is not to use uuencode to transfer these files,
but to use xx-encode, which produces files which look almost exactly
like uu-encoded files, but they use a character set which is
IBM-proof.  If you are using an IBM mainframe as your host computer
and you're having trouble decoding files, this is most likely your
problem.  Solution: 1) find a kind soul who is willing to uudecode the
files, xxencode them and send them to you, 2) get the files via FTP,
which should be EBCDIC-proof, or 3) get a better computer that uses
everybody else's character set. :-)

Almost all of the problems described above can be checked by using
GIFTEST to check the GIF file's integrity on your host machine before
you download it.  I have recently added the source code for GIFTEST to
the archive at bongo.  I highly recommend that you get a copy of this,
even if you only occasionally have problems with your GIF files; it
runs in only a few seconds, and has the potential to save you hours of
download time!