Can't even make transparency? Man... That must suck... And yes, JPGs are evil. I'm sure Bigboi's sig would be at least 10 times smaller and less crappy if it were a png instead, as the large red pools of mud would be compressed as though it were only two or three pixels long. :\
As for Roboashura's, I'm afraid I've given up hope for the moment. Practice drawing more!