In the Web World, there are two main formats for graphic files–jpegs and gifs. If you’re not creating web pages, this may not be important to you, but you might find the differences in their approach to be interesting.
GIF stands for Graphics Interchange Format and rhymes with “Jiff” (like the peanut butter), though most people pronounce it with the hard “G”. The format is limited to 256 colors at a time, so it tends to work better with graphic images (non-photographic). 256 colors may sound like a lot, but full-range color has millions of different hues and values, and a full-color photo saved as a GIF will show banding in gradients and have a pointillist quality to it. For graphic images, you’ll have a very sharp reproduction with nice, crisp edges. Once the file is saved, you can open it and save it over and over and it will always look the same. This is called a “non-lossy” compression. GIFs also have the benefit of being able to show multiple frames for animation.
JPEG is named after the Joint Photographic Experts Group. With a full-range of color, this is the format of choice for photographic images and the one your digital camera is most likely to use. The downside of JPEG is that it’s a “lossy” compression, meaning that saving a file to JPEG format throws away information that you can never get back. You might not notice this in a high-quality JPEG, but a low-quality JPEG will show you that the image is broken down into groups of 8×8 pixels and then approximated. A higher setting gets this approximation close, but a lower one may reduce the 8×8 block to a single color! Even if you save in high-quality, if you open it up and save it again, it will further approximate these blocks, degrading the picture quality each time (so keep this practice to a minimum). Most cameras have high-enough resolution that you can compress them pretty well once or twice without noticing “compression artifacts” on a print-out, but when doing web-work, one has to strike the right balance between file size and aesthetics.
So there’s your education in image degradation. See you next month! – j
Author Bio:
Jay Scheuerle, our Creative Services department's Art Director, could have been a doctor, but chose to work amongst us mere mortals. An even-tempered designer and telescope enthusiast who's been shutting out co-worker chatter for more than nine years, Jay sees the angles others don't. 
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