Hi Daniel, I don't know if you ever figure this out but here's what I did to change mine. (See instructions below). My new thumbnail is now pending approval, so it must have worked. (I just did it few minutes ago)! Good luck. :) 1. Click on ‘Teacher Settings’ (Top right-hand corner) 2. Click on ‘Teacher profile’ (left panel) 3. A menu will drop down. 4. Click on ‘Video’ 5. Scroll down to ‘Upload Video Thumbnail’ 6. Click on ‘Upload Video Thumbnail’ 7. Upload Video Thumbnail Note: Video Thumbnails must be at least 700 pixels in width and 400 pixels in height and cannot exceed a height of 1200 pixels.

*figured