Understanding File Formats

Different file formats serve different purposes. Some formats compress data to make the file size smaller on the disk, whereas others are used to make a file compatible with another software program or the World Wide Web. The format you choose will depend on how the image will ultimately be used. It is important to know what saving an image to a specific format will do. At worst, saving a file to the wrong format can damage it; at the very least, it will inconvenience you by losing the ability to place the document into another program.

Photoshop CS can open 29 file formats on the Mac and 26 on Windows, and save to 18 file formats on the Mac and 16 on Windows. With the addition of plug-ins that attach to the Import and Export submenus, Photoshop supports even more, which means it is a great program for converting files to make them compatible with other software programs. A complete list of file formats, what they do, and how they operate can be found in Appendix B.