I have no idea whether Spotlight uses the Finder's facilities to draw thumbnails or not, but I suspect not. I just tried a little experiment: I opened a Spotlight window then went about checking the little boxes on the side so that it showed stuff in my home done in the last year that were images and the search was for psd. All my psd files have a built-in thumbnail, as I set the preference for Photoshop to automatically create one when a file is saved. There were about 300 such files, and it took a noticeable amount of time for all of them to get a thumbnail. I then open my home folder in the Finder and did a Command-F, typed psd in the name field, selected kind: image and set the View option to icon, and then set icons to 128x128. The Finder was returning results as fast as I was doing this, and all the thumbnails were instantly just THERE--while the Finder does not cache thumbnails it has to draw, it does use thumbnails if they are present.
So my tentative conclusion is that Spotlight is behaving as the Finder does when there is no thumbnail present, namely it uses QT to draw one. And, like the Finder, does not cache these.
My recommendation to you is to not use the Spotlight window for your searches, but try using Command-F instead. It is actually superior in a number of ways. I almost never use the Spotlight window. I don't really see the point of it. For a quick search I use the menu bar. For a more precise search I use Command-F.
Francine
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