Don't forget you can use Paintshop Pro, PHotopaint also. PSP has a downloadable demo--and is reasonably priced for someone that doesn't want to or can't afford PS. PSD format is available as most others and alpha channels are easy in both PSP and Photopaint. I don't have Bebop's set but I can see that an alpha channel on a layer would be just really neatto overlay on other textures.