I think you should try discussing this with the people from Mozilla
(either on their mailing-list or directly via mail with the people
involved with GSoC from the Mozilla Foundation - see if they already
have a page dedicated to GSoC 2007) as they will be the ones to decide
if they are intrested in such a project or not and will be able to
point the pros and cons of your idea.
Good luck!
Ion
To my mind if you have any ideas about graphics processing or in
Firefox improvement you should develop your graphics processing
library or add your code to Firefox project. If you know how to
improve image rendering module in this open browser share your
experience in Firefox community. You should read Hacking Mozilla
first. As far as I know jpeg is 'non-free' project but if you have
sources and it's not conflict with any law you can realise your idea.
Best regards,
Arseny.