Utility for converting animated .gif to single frame .png?

I have a lot of animated gifs that I would like to use by saving the individual layers as .png files.
I found a script for gimp but it appears to crop some of the layers so that it looks funky when I then load the individual images one after another. Surely there must be some utility that will do this “unlayering”… but I can’t find one.
Thanks!
PS - mac or pc… doesn’t matter to me. [import]uid: 16901 topic_id: 8532 reply_id: 308532[/import]