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Custom video thumbnails

How to choose the image learners see on a video before they press play, and which videos it works for.

How do I set a custom thumbnail on a video?

Select the video block, open the video menu in the block toolbar, and choose Custom thumbnail. The image panel opens, and the image you pick becomes the video's cover. Learners see it before they press play, in preview and in the published course. Custom thumbnails work on videos you've uploaded to Coassemble.

A good thumbnail tells learners what the video is about before they start it. Use a frame that shows the subject, a title card in your brand colours, or a photo of the presenter.

How do I add one?

  1. Open the screen and select the video block.
  2. In the toolbar above the block, open the video menu (the video icon).
  3. Select Custom thumbnail. It sits at the top of the menu, above Replace and Delete.
  4. In the image panel, upload an image or choose one from your library, Generate, Pexels or GIPHY.
  5. Add alt text describing the image.

The thumbnail shows on the block straight away. Thumbnails display at a 16:9 ratio, so a landscape image works best.

How do I change or remove a thumbnail?

Select Custom thumbnail again. The image panel opens with the current thumbnail selected, so you can choose a different image or remove it. With no custom thumbnail, the video shows its default cover.

Frequently asked questions

Can I add a custom thumbnail to a YouTube, Vimeo or Loom video?

No. Custom thumbnails are only available for videos uploaded to Coassemble.

Does the thumbnail change everywhere the video is used?

Yes. The thumbnail is saved to the video in your library, so every screen that uses the same video shows the new thumbnail.

What happens to the thumbnail if I replace the video?

It's removed. Replacing the video clears the custom thumbnail, so add one again for the new video.