I don't think it's much slower, but I woulnd't count on it being the same. It seems to run well enough on my machine, a 466Mhz with 136MB RAM....
With Image Editing (paint programs specifically) the more memory you have the better off you are. It also helps of you've got you're OS running smooth.
GIMP 2.0 doesn't offically support 98 or ME, however it does appear to run fine, at least for me on 98se. I'm considering dropping a 256MB stick in my machine to replace the 16MB one that came with it originally, but I'm not sure if it's worth the effort since I'm planning on replacing the whole supid thing. If I did do that replacement I think I'd be set for most image editing that I'd be doing here.
As for animated stuff, that can really get big... I've only done a bit here and there with Animated stuff, nothing to major. Best left for a more powerful system.
As for what can be done with the Gimp... just about anything Photoshop or PaintShop Pro can do, so long as you're willing to put the time and effort to learn how to do whatever you want to do.
I had some images saved, artwork that someone who was in the GIMP Art group at Yahoo was doing... nice stuff, but she was an artist and was working with a tablet, most of what I've used it for has been some more basic editing.
As an idea of some of what can be done with the GIMP are as follows:
http://gug.sunsite.dk/gallery.php?artist=125
I don't know if this is the person I was thinking of or not, but she's got some nice looking stuff.... if I find the CD that I might have burned those files on I'll post a pic or two. (BTW, they have some tutorials and whatnot on that site as well).
I've included a pic I did for my Grandmother... it's a cousin of mine, his baby picture put on a scan of a comic from the Parade magazine that comes with the Sunday newspapers. Using GIMP I color-corrected the faded scan of the baby pic, did the editing to the scanned image of the cartoon (in multiple layers) and pasted the two together (which I think I had to not only scale the baby's face but also rotate it into position to fit the cartoon). In the process of doing the image I also had to put in a new band on the reflector on his head, so that (as you can see) was added in using stroked paths. (The printouts looked pretty good, they where wallet size as I recall).
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