I think it's unlimited.
I did a Google search anyway, and found this:
http://www.screenmate.net/faq.htm
quote:
Q. What is the maximum number of Frames in a Gif image?
A. There is no maximum number. The amount of frames depends on the amount of RAM you are using.
And another reference:
http://www.01network.com/services/animation/animation.htm
quote:
GIF files can use up to 256 colors and can contain an unlimited number of frames, although using too many frames creates a very large image which takes a long time to download.
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