It really should "just work" if show preview is checked for the folder. Occasionally the Finder has a mental melt-down and displays generic icons instead. When that happens a restart of the Finder usually fixes it. Here's something else to try (and I actually prefer it for browsing images):
1. Go to the folder and open it in Finder
2. Hit Command-f to bring up the search window
3. Click on the name of the folder in the search window toolbar to escape from the idiotic "This Mac" default
4. In the Kind option, click the double arrows on the box after "is" and select Images
5. All the images should now display in the window
6. As a bonus feature, down at the bottom of the window you'll see a slider, drag it to change the size of the thumbnails--you can go all the way up to about 512 pixels, which is why I like it for browsing images
If you don't get custom thumbnails in the search window either, something is seriously borked.
Francine
Francine
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