Image thunbnails looking grayed in explorer

[Perrupa]

I installed TweakUI on my girlfriend's computer for her to change the default shortcuts on the "Save As.." Dialog and that's the last thing either of us recall before THIS (http://www.uoguelph.ca/~cmarlow/crapcons.PNG) happened.

All the thumbnails for pictures in explorer are "greyed out", the picture is still visible it just looks like you're looking at it through a dirty window :p

Any ideas on how to remedy this??

Thanks

Peace