Optimizing the Compression in JPEGs

JPEG images don't have palettes as GIFs and PNGs do. Instead, the JPEG format compresses the visual information in an image by making it more efficient and tossing out information that the human eye isn't likely to miss. Too much compression gets rid of too much information, and image quality deteriorates noticeably.

GEEKSPEAK

Compression in a graphics format such as JPEG makes a lighter image file by losing a portion of the visual information. Too much compression gets rid of too much information, and image quality deteriorates noticeably.

Good graphics software allows you to specify the amount of compression in a JPEG file by adjusting its quality. There's no hard-and-fast rule for the best quality setting. It all depends on the amount of information in the JPEG.

To optimize a JPEG, play around with the level of compression and see which quality setting works the best. There's usually a point at which the image quality degrades significantly. When you reach this point, just go back to the previous level of compression.