Do you mean avatar or sig? Avatar being the little picture by your name. If you're looking for one of those it's really quite easy to do and to make it look decent. All I ever do is find the pic I want to use and make a 100 x 100 cut of it. Then I mess with whatever I need to like contrast, levels, hue saturation etc, but thats photoshop stuff mostly. In any case, find the pic, cut it out, make it into a jpg file. Then adjust the quality of the picture as needed to get it under the file size limits. My avatar is 100 X 100 and less than 5k. I think it looks pretty decent myself.
-Karrde-