User blog comment:Penguin-Pal/Image uplaods help/@comment-32129972-20121125164615/@comment-4018164-20121205172613

I don't know bitmaps are supported in all operation systems. Anyway, you would probably not be able to achive transparency in .bmp files- on this forum they tell how to achive that, but it will just give ou a headache, so ii think .png would work better for files.