JPEGView provides a number of options for controlling how it handles images by default. These are collectively known as the preferences options, and can be accessed via the Preferences… menu item in the File menu. The different settings are grouped into five categories — Opening, Monitors, Colors & Quantization, Saving, and Miscellany — and you can select which set to modify via the pop-up menu near the top of the Preferences dialog. Each category and its corresponding options are described in detail below.
Opening Preferences
The settings in this category allow you to change JPEGView’s default behavior when opening new images.
Use full screen windows — This option controls the automatic use of JPEGView’s full screen windows. Initially this is set to “Ask first for large images,” meaning that when an image is too tall to fit on the screen, JPEGView will stop to ask you if you wish to open it in a full screen window. If you instead select “Always for large images,” JPEGView will automatically use the full screen for images that need it, without asking first. The “Never, even for large images” selection will cause JPEGView to open all images in normal windows, again without asking. Finally, by selecting “Always” you can force JPEGView to open all images in full screen mode, regardless of their size.
Automatically fix incorrect file types — By checking this option, initially on, you tell JPEGView to quietly fix any incorrect file types it finds on opened images. Note that this is different from the “Scan and Fix Image File Types” button in the Open dialog. Whereas the latter option affects whole groups of files without opening them, this option applies only to files you open with JPEGView. For example, if you open a JPEG file that is incorrectly indentified as a GIF, JPEGView will automatically change the file’s type to JPEG with this option selected. In general, this option is simply a quiet means of keeping file types straight without your intervention.
Open only one image at a time — If you find yourself using JPEGView to open only a single image at a time, you can check this option to simplify your life. With this option turned on, JPEGView will automatically close all open images before loading in any additional images. This helps keep your desktop clear of multiple images and saves you the trouble of closing every image manually before opening a new one.
Monitors Preferences
These preferences options control JPEGView’s use of multiple monitors. Note that if you only have one monitor, it makes no difference how these are set.
Open new images on the… — These settings allow you to choose which monitor JPEGView uses for opening new images. In general, you probably would like to set this to the “Deepest screen,” meaning that JPEGView picks the monitor that can display the most colors. If you choose the “Largest screen” instead, JPEGView will use the monitor that has the largest screen area, measured in pixels. Finally, selecting the “Main (menubar) screen” option places all new images on your main screen, defined as the monitor containing the menubar.
Open statistics window on the… — This option is similar to the previous option and controls on which monitor you wish to have the JPEGView statistics window. The usual setting for this is the “Main (menubar) screen,” which always places the statistics window on your main monitor regardless of which monitor you have chosen to open new images onto. The “Same screen as new images” selection tells JPEGView to bring up the statistics window on the same screen you selected in the previous option.
Colors & Quantization Preferences
The items in this section control the default color palettes JPEGView uses to display new images.
Quantize 16 and 32-bit images — This setting controls the automatic use of two-pass quantization on high-color images. The initial value, “Always,” means that JPEGView will always calculate an optimal palette using two-pass quantization for such images, even if there is a previously created color palette stored with the image. The option “Only if the image has no palette” causes JPEGView to use the color palette stored with the image if it is available; otherwise, it will calculate its own palette using the two-pass quantization. Choosing “Never” will turn off JPEGView’s automatic quantization and will always use the system palette for new images, or the image’s own palette, if one is found.
Dither quantized images — Because two-pass quantization in general produces a very good set of colors for a given image, it is often desirable to turn off dithering altogether. Rather than forcing the issue, this option allows you to explicitly specify whether or not JPEGView should dither images when it has calculated a quantized palette.
Use image palette for other images — Checking this box will instruct JPEGView to use the image’s internal palette — if found — for images that don’t quality as high-color images (i.e., images with less than 16-bit color). If this box is not checked, JPEGView will default to using the system palette for such images, regardless of whether or not they have an internally-defined palette.
Saving Preferences
These selections control which boxes are checked in the save dialog by default.
Save quantized image palettes — This option determines the setting of the “Save quantized palette information” checkbox in the save dialog when the image you are saving has had two-pass quantization performed on it. The default option, “Only if the image had no palette,” means that this checkbox is checked only if JPEGView was unable to find a color palette with the original image. Your other options, “Always” and “Never,” tell JPEGView to either always check or to never check this box when the save dialog is presented for a previously-quantized image.
Save QuickTime PICT previews — Checking this box means that the “Include preview (thumbnail) image” box in the save dialog will be checked automatically whenever you choose PICT output.
Save JFIF thumbnails — If you check this box, JPEGView will automatically check the “Include preview (thumbnail) image” box in the save dialog whenever you select JFIF output.
Default to PICT output — By checking this box, you can force JPEGView to always have PICT output selected in the save dialog, no matter what format the file was originally saved in.
Miscellaneous Preferences
These preferences settings control the JPEGView’s behavior in various other situations.
At startup — This allows you to control what JPEGView does when you initially start it up. Normally, the “Open dialog” option is set, meaning you are immediately presented with the standard open file prompt. You can also choose “Begin slide show,” which will automatically start up the last slide show you ran, or “Slide show options dialog,” which allows you to immediately set the parameters of a slide show which you can initiate right away. Finally, choosing “Nothing” means that JPEGView will do just that on startup.
Open statistics window on startup — Checking this box causes the statistics window to automatically be opened at startup, on the monitor you selected in the Monitors Preferences.
Ignore minor errors during slide show — A check in this box means that JPEGView will not report any minor errors — for example, out of memory conditions or corrupt image files — during a slide show. Without this option, your slide show can be rudely interrupted with dialog boxes and error messages; selecting this helps keep things nice and quiet.
