Does anyone know of good (and preferably free/very cheap) programs to reduce the sizes (the kb size, not actual size) of images? I've google'd up some feasible looking ones, but I was wondering if there were any other hidden gems that people knew about. Thanks!

p.s. does crunching an image's size affect its quality? I can't notice much of a change, though I also can't believe that the file size would magically shrink without something happening to the image.

IrfanView is a good one and free for non-commercial use.

have a read of this topic in creative arts from a while back

For me, I convert images to less large formats (I think like, .jpegs are smaller or something) and lower color counts and stuff. Usually works fine.