hey i am having a wallpaper fail for my ipod touch. i have tried all morning to set it in the wallpaper section of settings. but when i turn my touch off and on again the front wallpaper is still black :/ not sure what is going wrong. i have had a wallpaper before. and i recently wiped my old images to pu ton new wallpapers (that were the right size) and i am not sure what the problem is. is there a file size limit?