Avatar 39K, sig 165-168K... now, multiply that by, oh, say, 20 posts per page? I just don't like the load time avatars/sigs add. Especially on some boards where there appear to be no enforced size limits. I do appreciate that some boards allow you to turn them off entirely. In which case all the effort you put into your graphics will be wasted on someone like me.
Your avatar is mostly background. Crop out the extraneous stuff, shrink slightly, optimize, and I'll bet you could come up with something <5K that conveys the same overall gist without a noticeable difference in quality.