I downloaded the Windows version of GIMP, it seems a lot like Fireworks but seems to hog my CPU
I use GIMP and its didnt take so mush memory.
He didn't say memory.
But I don't agree anyway, if you have a few 8 MP images open at the same time, and you start working with several layers for each, it's going to each up CPU and Memory.
Imaging programs aren't really tailored to low-end budget systems, especially for doing any sort of professional image work.
If you're making a small avatar or something like editing the red-eye out of a photo, it shouldn't be causing much of a problem. However, if you're working with large RAW Photos, or jpegs right off of your point and shoot or SLR camera, try compressing the 5, 6, 7, 8, etc. MB image into something a little smaller before editing it.
Or, get a faster computer.
Mac's do this sort of thing very well also, that's what they're made for.