Understanding File Formats in Photoshop

Web browsers can display images in several ways. The fastest, easiest, and most compatible solution is to use graphics that the majority of browsers can display natively, in-line (that is, consecutively with text). Except for some browsers that display only text, the most commonly used browsers can handle only files saved in GIF (Graphics Interchange Format), JPEG (Joint Photographic Experts Group), and, in some cases, PNG (Portable Network Graphics) formats. Browsers can display other types of images if users have installed the appropriate helper applications or plug-in. For example, if you’re browsing and click a link that leads to a PDF (Portable Document Format) file, your browser can display the file if you’ve installed the Adobe Acrobat Reader plug-in and the Adobe Acrobat Reader application. (Most people have it; if not, most sites that include PDF documents also include a link to Adobe to download the plug-in or the stand-alone free Acrobat Reader software.)

Flash animations are another kind of image that requires a plug-in to view. However, formats other than GIF, JPEG, and PNG are beyond the scope of this book. All you really need to know is how to choose between these three file formats.