Understand how VidFlow AI creates thumbnails for generated videos and what fallback paths it can use.
Content reviewed: October 18, 2026.
How thumbnails are created
VidFlow AI can generate thumbnails in the browser by capturing a usable frame from a same-origin image or video source.
Best path
- A same-origin Start Frame image is the most reliable thumbnail source.
- If the completed video is stored locally, the browser can try decoding the local video.
- For provider-hosted videos, VidFlow can load enough of the video to create a thumbnail when the source is accessible.
What is stored
Thumbnail images are small WordPress media attachments. Pro project video cards use the same general thumbnail fallback behavior as the Video Library.
Common blockers
- The browser cannot decode the video.
- The provider URL expired.
- The proxy request is blocked.
- Temporary file creation is blocked.
- Image or video CORS behavior prevents capture.
Thumbnails and full-video storage
Thumbnails can be created while optional full-video storage is off. If one is missing, reopen the video in the admin and check that its source image or video is accessible.