User blog comment:EthanConquistador/Cleanup the Wiki and Custom Thumbnails/@comment-6812733-20131212122941/@comment-24499539-20131212130309

Um, it's this problem is having this, you can check the account of the additional features, and see that the Custom Thumbnail section is enabled or not, it may have been a try, I re-read the page of the Video Thumbnail page, it says "If your account is vertified and in good standing" that means you can grant the custom thumbnails. https://www.youtube.com/features