Selling Video Blog with Great domain (w/ traffic)

Hello,
I am selling this great site.
The reason I am selling it is because, I can't figure out why it doesn't show thumbnails. I had a theme before which was good and thumbnails were showing , but somehow that theme stopped working. I tried to change the theme, but thumbnails were not showing anymore. So, you have to fix it

It had a good traffic when everything was working:

But after the problems and hosting problems too the traffic dropped but now it is increasing again.


The site has 16.5k indexed pages on google
24k posts
340k comments

Thank you