N-Up / Contact Sheet (enhancement request)

[GoogleCodeExporter]

N-Up or Contact Sheet would display multiple images at one time similar to the 
"Contact Sheet" function of Preview.

Advantages:
 - when browsing hundreds of files, this makes it much quicker for the eye to locate an image of interest.

Cons:
 - would be tricky to integrate with the current navigation system; perhaps in contact sheet mode this changes.
 - loading performance might not be as quick as currently.



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Just bought Xee after 10 minutes of use. It's great! I can finally archive of 
those thousands of little clipart files and browse them with Xee. 

Original issue reported on code.google.com by balthi...@gmail.com on 15 Dec 2014 at 11:42