Custom thumbnails for youtube videos

[romanbond]

It may not be directly related to SEO, but I was wondering what is the criteria for becoming YouTube partner so you can upload custom thumbnails for each video. Our YouTube account is in good standing, but this feature (custom thumbnails) is still deactivated (showing gray button).
Is there is certain number of videos/views that Google wants before it can allow you custom thumbnails. Any info would be appreciated. Thanks!

[Aeronet]

I saw in a tutorial that you have to monetize your account (just an option to activate in the advanced features of your youtube account) to activate the custom thumbnail option.

[PhilNottingham]

There isn't really special criteria, you just have to be in Good standing then click the "Allow advertisments to be displayed alongside my videos" icon on https://www.youtube.com/account.

Unfortunately there's no way to become a YouTube partner without first accepting ads. YouTube are very unspecific about it, but being a "partner" basically means allowing ads on your channel. It's not as exciting as it sounds, but they're adding more features to make allowing ads more appealing.