February 22, 2009

JPEG, GIF or PSD?

Kiery

In my last post I talked about the different picture file formats that digital cameras can create. If you are editing your digital photos with computer software, you may be confused about which file format is best in this situation. Here's the scoop.

First, a recap of the JPEG ("jay-peg") format: it saves your picture in a smaller package (file size) by compressing the image data. Doing so lets your camera save more pictures in the same space on your memory card or hard drive. The draw-back is that this compression actually results in some of the picture information being thrown away. If your photo is compressed too many times, too much information is discarded and your picture quality suffers. For this reason, it's generally not a good idea to use the JPEG format when editing your photos. But JPEG is appropriate for saving pictures in your camera, emailing pictures to friends or posting pictures on a web page.

GIF format (pronounced either "jif" like the peanut butter or "gif" with a "g" like in "goat") is best used for graphics like logos and pie charts. It can use only 256 colors in its files, which makes them nice and small for the internet, but does not generally produce realistic results for photos. (JPEG format uses up to 16.7 million colors.) So GIF format is not commonly used for digital photographs.

PSD (pronounce each letter like "IBM") format is specific to Adobe Photoshop products like Photoshop Elements and the professional version of Photoshop. In order to create, display or print PSD files, you must have a Photoshop program on your computer. If you are editing your images using a Photoshop product, saving a copy of your picture in PSD format before you begin gives you the best quality. PSD format is not compressed, so no information is thrown away during the saving process. PSD format can also use 16.7 million colors, so your photo keeps its realistic appearance. But you will need to save your edited result in a different format (JPEG or TIFF, for example) if you want to share it with someone else who does not have a Photoshop program.


So each of these file formats---JPEG, GIF, PSD---is appropriate in some situations but not in all. Use JPEG files for photos in email and on web pages, PSD files for editing photos with Photoshop products and GIF files for logos and other simple graphics that have few colors.