lucy24 - 9:24 am on Feb 4, 2013 (gmt 0)

obviously it doesn't need to index my image files in order to produce the snapshot

Apples and oranges. The original post was a question about image search. I'm not sure how Preview even entered the discussion, since it has absolutely nothing at all whatsoever in any way-shape-or-form no way nohow to do with image indexing.

I think we are all agreed that Preview can only be kept out of files by brute force. The kind that has an [F] at the end.