I've just published a jQuery plugin called jQuery Tiles Gallery on Envato Marketplace.
This plugin is able to arrange images in a complex and random generated grid. Images are preloaded and put into the grid to fit at best theirs cell. So, a great advantage of this plugin is that you don't have to prepare all images of same size or proportion.
The plugin is available here http://codecanyon.net/item/jquery-tiles-gallery/2281417?ref=darkoromanov just for 5 buckets.

