(Mountain Lion, MacBook Pro) In Finder, I have a bunch of movies that are shown as thumbnails. MOV files, 3GP, various formats, you name it... However, most of the thumbnails do not represent the corresponding movie very well. Is there any way in Finder / QuickTime that I can set the poster frame of a particular movie? Doing a Google search, it seems that an option to "Set Poster Frame" existed at one time in QuickTime, but I don't see this option anywhere in the version that I'm using.