You can upload scans from negatives as well as transparency film (E6) as long as the are scanned to a big enough size. 

PLEASE NOTE:
It is almost impossible to clean up scans from 35mm films to such a degree to compete with current dSLR technology. If you have medium or large format film scans, you might want to submit those, but considder sending us a test sample first.

If the image is not absolutely clean and noise free (with sufficient Colour Depth) it will not pass the quality controls, and will be rejected.