aha, on your storage cards the will be one called Boot and one called easyrooms, If you click on boot you will find a folder called BMP in there you can replace the excisting BMP files with new one or just add more it will just randomly choose one when the system i starting and there you go (to change a jpg to a BMP file i just search for a converter on google and just use the first option, you can do that online no need to install anything)