In the Finder of my mac, it often happens that some photos in a folder are displaying wrong previews. The set of photos which have this problem is random and unpredictable: sometimes among 10 photos in a row there is one with a wrong thumbnail. The wrong thumbnail is always another photo in the same folder. Rebooting the machine does not help, which means the wrong information is stored somewhere. When I duplicate the photos (as an experiment), the new copy is OK.
I wonder if there is a way to force refreshing the thumbnails.
MacBook Air (13-inch, Early 2014), OS X Yosemite (10.10.2)
I have also asked this question on https://discussions.apple.com/thread/6988345 but received no answer yet.