Actually, for the current issue, the bot to use from the pywikipediabot-project would be upload.py with the -wiki option. For example: "upload.py -lang:commons -wiki:en Imagename.png"
imagetransfer.py is meant in case you have not yet found the image, but have an article to which you want to add the image which does have interwiki-links. It then looks for an image in the interwiki-linked pages.
Andre Engels
Well, reinventing the wheel seems to be a common problem. :) You might just head over to the pywikipedia bot project at http://sourceforge.net/projects/pywikipediabot/ and use the imagetransfer.py bot for this task...