Fit XHTML image width to chat window size
This ticket originates by [GajimChat:2016:01:01:16:57:31 Johannes].
problem
Ugly and, sometimes, unusable horizontal scrollbar upon an image wider than chat view box.
analysis
When width of image is wider than chat view box, user may end up with a very large horizontal scrollbar, something that does not look good.
enhancement recommendation
Fit images to chat width.