[mcphage]

You’d probably want it to match YouTube’s preview image, so if your reader sees the video on YouTube proper at a later date, they’ll recognize it. I’m not sure of a good way to do that, since it’s not necessarily a screengrab from the middle of the video.

[dylan604]

Does YT not allow you to set a poster frame? I'm not a heavy YT poster and am much more familiar with Vimeo that does allow a custom poster frame. In that case, you could ensure the poster is the same everywhere.

[snailmailman]

I don’t know how possible that is anymore. Youtube is letting creators A/B test thumbnails and titles now. So the thumbnail and title isn’t consistent between users or page visits.

It’s tripped me up several times. Although it’s unclear how much it’s the new feature or creators manually trying to game the algorithm by shuffling the title and thumbnail around.

[extraduder_ire]

I believe it's consistent per user (account or logged out) while the test is ongoing then switches to the "winning" thumbnail for everyone once it concludes. Tests can be re-run as many times as you want though.