In addition to simply viewing your images, JPEGView can also give you specific information on how it is displaying those images and what the memory requirements are for each image you currently have open. To see this information, make the JPEGView Statistics window visible by selecting it from the Windows menu (‚åò0). This window gives you a frequently updated list of many important bits of information about the currently active image. Below is a summary of what each field describes and what you might find displayed there.
File: This is simply the name of the original file from which the image was read.
Status: This field tells you the cropping and banding status of the image; it will also indicate if the active image has been found to be corrupt. You can get cropped images either by using the Crop & Zoom function in the View menu or by opening a compressed PICT that had been previously cropped. Banded images come from QuickTime-compressed PICT files that were compressed under low-memory conditions. See the section on JPEGView Questions & Answers for a further explanation of banding.
Image Size: This tells you the width and height of the original image in pixels, before any scaling performed by JPEGView. For cropped images, this field tells you the size of the cropped region, with the original size given in parentheses immediately following.
Onscreen Size: This is the width and height of the image you are actually seeing onscreen. If the image has been scaled, the scaling factor is given in parentheses.
Colors: This is the number of colors given by the image data, given in the same way you’re used to seeing it in the Monitors Control Panel, i.e., “Thousands” means 32,768 and “Millions” means 16.7 million.
Palette: This is the currently selected palette for the image, as seen in the Colors menu. Dithering is also indicated, if selected.
Compression: This field tells you the type of compression used on the image and, if the information is available, the vendor of the compressor and the quality factor used in the compression. There are a number of possible values that can be seen here:
• Photo — JPEG for QuickTime-created JPEG images in PICT files.
• QuickTime JPEG for QuickTime JPEG images put into JFIF files.
• IJG JPEG for JPEG images created by the Independent JPEG Group’s (IJG) code.
• Adobe JPEG for JPEG images created by Adobe software.
• Unknown JPEG for any other JPEG images.
• GIF — LZW for images compressed using GIF.
• Animation for QuickTime PICT images compressed with the Animation compressor.
• Graphics for QuickTime PICT images compressed with the Graphics compressor.
• Compact Video for QuickTime PICT images compressed with the Compact Video compressor.
• Video for QuickTime PICT images compressed with the Video compressor.
• None for uncompressed or raw PICT images.
For QuickTime PICT images, the quality factor used during compression is given, in the standard range from 0.00 (worst) to 4.00 (best). For JFIF images, which do not store the original quality factor used in compression, only an estimate of this quality factor can be made from the tables stored in the image. Currently JPEGView only estimates the quality of JFIF files created by the Independent JPEG Group’s code, which uses a slightly different quality scale, ranging from 0 (worst) to 100 (best).
Format: This is the file format that the image was saved in. Possible values include PICT, JPEG, JFIF, and GIF.
Image Length: This is the length of the image, given in kilobytes. If the image was compressed, then the savings gained by compression is computed and displayed either as a percentage for small compression gains (e.g., 60% compression, meaning that the compressed image is 60% smaller than the original) or as a ratio for highly compressed images (e.g., 7:1 compression, meaning that the compressed image is 7 times smaller than the original).
Offscreen Buffer: If JPEGView has created an offscreen buffer for the current image, its size is displayed here.
Free Memory: This represents the amount of memory JPEGView has remaining. Please note that this value is never absolute, because JPEGView always tries to leave some extra memory (about 100k) available for internal use. Thus, JPEGView may not permit you to open an image even though there appears to be enough memory.
