[galaxy-dev] Upload of images - jpg/png - "binary file contains inappropriate content"

Hi all, I would like to be able to upload images to my Galaxy instance - in particular jpg/png to data libraries. I can't however find out how to overcome the problem of inappropriate content in binary file. How to go about? When I create a sniffer class in the galaxy.datatypes.images.py that always returns true (for testing purposes) I still don't get the jpg uploaded without an error (sniffer is incl. in the datatypes_conf.xml ). class Jpg( Image ): file_ext = "jpg" def sniff(self, filename): """Determine if the file is in jpg format. """ return True It seems I'm missing something obvious and could use some help. Cheers, Jelle