The second image has a more eye catching look to it. The stop logo is front and center, the wall behind you is more clear and more realistic. My only suggestion, try not to seem so serious. Maybe not a smile in this particular thumbnail but at least a friendly face that is inviting rather than one that looks upset. Remember, the image need to evoke a desire to click on it and anger only works on very specific topics.
I would definitely try to retake the image to get a clearer image, but also potentially try to show case one of the bad habits IN the picture. I think the font in the upper one is better than the second one, but the 2nd one has a bit better layout for word alignment. I tend to put image of person on right and words on the left. Best of luck.
OH - another quick tip. Look up your topic in YouTube and see how the best viewed videos look for their thumbnails.
100% the second. Do you post your face on all thumbnails or not? Because having a familiar face is something people will easily click on. If you don't usually do this, think if you want to keep doing this or not.