I've been trying to figure out this on my own for weeks, but now I give up. 'Custom thumbnails' feature on YouTube is such a controversial one, it was changed so much... so much that even FAQ on YouTube doesn't fully describe it's features (as I see).
I have a YouTube channel for one of my websites. This YouTube channel is main marketing force for my website - it brings all the boys to my yard (I mean, website). So I have to use all the hacky-tricky stuff to increase my visibility on youtube. And damn, those custom thumbnails are giving me hard times...
As far as I understand, this is current state of 'custom thumbnail' feature: "If your account is in good standing, you may have the ability to upload custom thumbnails for your video uploads." (c) https://support.google.com/youtube/answer/138008
My channel has good standing, has more than 50000 views. So why the hell my account is still not eligible for this feature? anyone have any idea?