the dimensions of the art is irrelevent, it just needs to be in the same format as rpg maker sprites. I.E. top row, is walking down, second row is wlking left, next row is walking right, and bottom row is walking up( if 8 directions follow the format in the help file ). As for if it's for big characters or not( images with $ in the name ), it does not matter as well, it should work with both. :)