JPEG images cannot be animated, although a related format called MPEG will animate in full-color the way QuickTime does. When you save your files, the palette will be restricted further because your system will automatically discard the colors that aren't being used. This is known as optimization . The more unnecessary information that you can remove, the smaller the file size will be. For this reason, you may wish to consider transparency in your image.
Transparency can be both useful and harmful.
When you utilize transparency, you can help to reduce file size and enable an image to blend better with its background. However, if the outline of your image is a serious mis-match to the color on which it appears, it can be jagged and ugly. If you know in advance that you want your image on a green background, it is best to actually create your image on a green background, and set that color as transparent. If you do this, the image program will anti-alias the border color to match the green background. Copyright 2001 INT Media Group, Incorporated All Rights Reserved.