hopefully this will help you more... a screenshot from resolve which has thumbnails on the timeline... as you can see the cti is in the middle of a thumbnail, which is obviously NOT an image of the specific FRAME... it spans the frames, but gives you a general idea where you are like a landmark..... ???? hope that makes sense. to see individual frames you have to look at the program monitor of editor and scrub through stuff frame by frame or scrub in general to find where you want to do your editing ( make cuts, etc. )
if you follow ann's suggestion you'll see the thumbnails.
just for fun I thought I'd add some info....for resolve and ppro users.
the thumbnails DO NOT INDICATE INDIVIDUAL FRAMES.
they bridge a range of frames and are generated ( shown to you in timeline) to give you a sense of what you are looking at in general ( as a clip and portions of that clip in general ).
To see individual frames you have to look at your program monitor and scrub through your timeline etc... there is no way any editor can show you thumbnails ( basic overall clip visual elements ) as individual frames....