I'm going to teach you how to make clickbait posts

Click the "insert a link" button http://imgur.com/a/AzTLm

Insert the URL of picture you desire to be the thumbnail. But leave the hyperlink area, the area between the [ ] blank. Make sure this is at the very top of the post, as the thumbnail is always the first picture listed. Now put whatever you want below it.

http://i.imgur.com/hLyGXDI.png?Noredirect

I once had a thread that started with -2 and reached +150 upvote later that day. So maybe this will change.

Truth is, it's hard to make good clickbaiting posts without having a few downvotes

Sadly