Horrible little devil.,
This review is from: Canon SELPHY CP800 Compact Photo Printer - Black (Electronics)
The printer will ONLY accept image files with the correct dimensions and EXIF data, and that's not even a guarantee that it will print off the USB/card slots. If you manage to get a picture it will print from USB/card, you can't crop it in the printer, and your options are very limited.
If you choose to install the even more horrible printer software, you'll end up pulling your hair out of your head. It's UNBELIEVABLY slow and seriously annoying.
I sincerely regret wasting over £65 on this crap.