When I disable lazy loading YT videos and trigger a HTML rebuild of the particular post, then the thumbnail is refreshed. But when enabling it again and rebuilding the HTML I get to see the old thumbnail again. Is there a way to clear the tumbnail cache of one video? Or is there a way to set/check …

This is more related to YouTube than anything else. When you disable lazy loading, the video iframe gets embeded directly which has direct access to YouTube’s API each time it get loaded. For lazy loading, we fetch the thumbnail from img.youtube.com/vi/id/maxresdefault.jpg instead. There are multip…

The thumbnail is updated on the YouTube side. In new topics it loads with the new one, but in the original topic it keeps reverting to the old one. As if Discourse has a cache. It even happens to this day :slight_smile: My quick fix now is to disable lazy loading, rebuild the HTML of the topic, it …

This is still an issue, also with new topics. Thumbnails are never updated, even if the YouTube video gets a new thumbnail. Removing the links, rebuild HTML, add the link again, all doesn’t matter. It forever keeps the old thumbnail. Can this be fixed please?

I’m seeing the same thing on a hosted site as well. Changed the thumb on YT but onebox is not updating. If I attempt to EDIT the post the preview shows the new thumb but doesn’t force the update on the post itself. If I tap/click the onebox in the post without hitting the play button, it updates …

Lazy loading YouTube videos doesn't update video thumbnail

Product Support

patrickemin (Patrick EMIN) September 25, 2025, 9:55pm 12

Hi, I still have the same kind of problems with YouTube preview images not appearing.

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Lazy loading YouTube videos doesn't update video thumbnail

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