Other File Formats
For the World Wide Web, GIF and JPEG are the two still image formats most commonly used. These are cross-platform formats, meaning that they can be read by virtually any computer browser including Windows, Mac, and other systems.
GIF is another lossless compression format; it stands for Graphics Interchange Format. GIF is an older format that was developed in 1987 by Compu-Serve but is still frequently used on the Internet and is compatible with all browsers. The format also supports animation.
GIF is often used for Web graphics and can be compressed a good deal with different color settings. You can set one of the colors as transparent, which is ideal for banners and other small graphics on the Internet. GIF can create very small files by saving as few as two colors (typically black and white) or sixteen colors for a basic palette. GIF also accommodates 8-bit color, giving you the option to save up to 256 colors. This is far fewer than the 16 million colors recognized by JPEG and TIFF. However, you should note that the user chooses which colors GIF will use, and they can come from any of the 16 million available from the 24-bit color library. A good image editor will list the colors contained in the GIF file and allow changes. GIF is an especially good file format for line drawings and graphics that use a limited number of colors. In addition, if you want to turn a series of photos into an animation, the GIF format is an easy way to go. Use an animation program that works with GIF files.
If your image has fewer than 256 colors, then there will be no degradation of quality when you choose to save it as a GIF file format. Since the format is not saving color information for unused colors, the file size will be reduced. But if your image contains lots of subtle variation in color, its quality will be greatly decreased.
The BMP (Windows Bitmap) file format is unique to Windows and often used by the Windows operating system. These files tend to be quite large and should usually be converted into JPEG, GIF, or TIFF files for personal or Web site use.
Before the Mac OS X, the Apple “picture” file format (extensions .pict, .pct, or .pic) was used by and was unique to the Macintosh. The Mac OS X now uses Adobe's PDF files (extension .pdf), which is a cross-platform file and can also be viewed by Windows.
Many software programs save files to native (proprietary) formats, which are designed to support the program's special features. For instance, Photo-Deluxe uses the PDD format, Photoshop uses the PSD (Photoshop document) format, and Paint Shop Pro uses the PSP format. However, most other programs will not be able to read these formats. If you want to use your image in this format with a different program, you will need to save (convert) your image to a common file format such as JPEG or TIFF.
To convert one still picture file format to another, use the Save As submenu under the File menu. When you pick Save As, also pick a new file format from the ones available within the program you are using. They are usually listed in a drop-down menu.
