im a novice here, but i would think image size would determine that.. due to fillrate issues. If you have a 640x480 image, it would be faster to do an overlay via drawimage? Havent tested comparisons, but on my card if i try to use a sprite over 256x256 as an overlay it kills my fps. im sure someone here will prove me wrong, as they usually do :) but thats my 2 cents for now.