AHHHHH.

Okay, need help.

I save some icons as .jpg, because otherwise my comp loses the colour integrity. They fade or they wash out if I don't save colour file, but those files sizes can often be too big. They didn't used to be - now, who knows? And .png icons I try ALWAYS fade and wash out, and .gifs lose all sharpness! All my recent icons are terrible, either because of this, or because I'm terrified of what will happen.

Help? I use Photoshop CS on a Mac.