On Youtube there's a new video feature where you can try out different thumbnail side by side to see which works best. On the connected video I'm trying that out. The three thumbnail variations are:
1. Zoomed in screenshot of gameplay containing two pieces of text and a circle at the bottom.
2. Zoomed in screenshot of gameplay
3. Regular screenshot of gameplay
I thought I would test it out and if you're interested in the results comment on this post with your prediction of which will succeed and I will update this post with the results.
(after doing this you may as well watch the video too)