OK, so the problem appears to be that tapping on a photo in the scope does show the preview, but the image shown with the preview is full size, so the "Open"/"Play" button near the bottom is not visible until after I scroll down. The preview should indeed show something smaller that doesn't blow all of the screen real estate.
This is not a thumbnailer bug, re-assigning to photo scope.
OK, so the problem appears to be that tapping on a photo in the scope does show the preview, but the image shown with the preview is full size, so the "Open"/"Play" button near the bottom is not visible until after I scroll down. The preview should indeed show something smaller that doesn't blow all of the screen real estate.
This is not a thumbnailer bug, re-assigning to photo scope.