Help for 23

Hi everyone,

I'm new to 23, and actually still on the search for the best [tm] photosharing service. So far 23 ticked all my requirements, yet there is one problem that I could not find an answer for:

I rated my photos in digikam before uploading, yet the rating is not available in the EXIF tags AFTER downloading the "original file" from 23 again. Also the MD5SUM is not the same. I dont need the rating on the files uploaded here, but when I download them again they should be "original".

Can you tell me what is stripped down from the pictures when uploading them to 23?

Thanks a lot & Merry Christmas
Frank