The Thumbnails tool imports the missing featured images of all your video posts in one go — for example after the server’s disk was full while videos were imported, or after image files were deleted. Open Videos → Tools and choose the Thumbnails tab.
What counts as missing
A featured image is missing when the post has none, or when the post has one but its image file is no longer on the server. Posts with a working featured image are not changed.
How it works
- Thumbnails are imported from the video details saved on each post, so the tool uses no YouTube API quota.
- The largest thumbnail available is imported, up to 1280 × 720 px.
- When a post’s image file is missing, the image is downloaded again into the existing Media Library item: every post that uses it gets it back and no duplicate images are created.
- Before each batch, the tool checks that the uploads folder of the current month can be written, creates it if needed — also when the content folder is set with a relative path — and tries to make it writable. If it still can’t be written, the import stops with a message instead of failing on every post.
Click Import missing thumbnails. The import runs while the page is open, so keep it open until it finishes. You can stop it, continue later, or reset it to start again from the first post. Errors are listed in a scrolling box below the progress.
Fixing a few posts
For a handful of posts, use the Import thumbnails bulk action in the list of videos, or the Import YouTube thumbnail button in a post’s Featured image panel — see Video image import. Both also repair images whose file is missing.
Developers: storage plugins that keep media files on other servers can report their files as existing with the cbc_attachment_file_exists filter, so the tool doesn’t treat them as missing.
Related: Image options · Update videos.