Its because of the size of the dp... the file size I think... try compressing it more or something... I'm not sure that its because of the width/height of it... as those limitations are usually bypassed when you have stuffplug... its generally the file-size...
if i'm wrong... /slap me... here you go... copy and paste this!!! /me slaps traxor with a smelly fish for being a dumb moron.
