Posting
YouTube thumbnails
YouTube shows its own auto-picked frame for Shorts, not the cover you build in Deploy. Here's why, and how to change it in YouTube Studio.
YouTube picks its own cover
#On the Media step, Deploy still builds a cover for your video: pick a frame, add text, or upload your own image. It goes out to TikTok, Instagram and Facebook as the thumbnail.
YouTube is different. YouTube Shorts shows the frame it picks for itself, in the Shorts feed, search, Studio and link previews, no matter what cover is stored on the video. Deploy doesn't send one there anymore.
Your video posts to YouTube either way. The cover editor on the Media step just won't change what shows up there.
Pick a different frame on YouTube
#Open the video in YouTube Studio and pick one of the frames it suggests as the thumbnail. That's the one place a change takes effect.