Hello, My problem is the following : I would like to create an image using the matplolib facilities and then insert this image in a <IMG SRC="*data*:*image*/???;base64 *.../> *element. Then using Gecko (mozilla) and python + xpcom, I would try to interact with this image (zoom ...). In order to succeed I feel I have to understand how a back-end is written. It seems I have to start with the Figure class. But then I can't find the image format, the way to return binary data or perhaps base64 data. I don't want to save the figure in a file et then read it with <IMG SRC="theFile.png"/>. The speed would be very low. What is the process to add a new back-end ? I wish the encode/decode base64 wil not take too much time for keeping the dynamism of gtk back-end (for instance). What do you think about that ? Thanks a lot, Cyril.