I would appreciate the thoughts of any javascript / css ninjas on how I can customise:
https://github.com/jdbartlett/loupe/blob/master/jquery.loupe.js
To have a circular zoom area instead of rectangular one? There is an option to set a css class for the loupe.
Please note that this is a question about the library linked above. I have already googled for other libraries. I want to keep the js as small as possible.