Images copied from iPhoto aren't searchable

Hi,

I'm on OSX 10.6.4 and iPhoto v 8.1.2 (424)

I copied a large batch of photos from iPhoto into a folder, then changed the names just by editing them in the Finder window. None of them come up in a Finder search, not unless I save the image with a new file name in Photoshop. There's a lot of these images and I don't relish the thought of having to open all of them up, save them again and change the file name slightly just to they can be found in a search.

If anyone knows a fix for this it would be much appreciated.