When streaming a Live, you can pick a thumbnail to your liking that will be displayed in the Live list.
Recommended thumbnail size:
1280 px × 720 px (16:9)
If you don't set one yourself, a screenshot of your Live will be set as your thumbnail.
Additionally, thumbnails can be changed even during the middle of a stream.
* Picking a thumbnail that matches the content of your stream is recommended.
* If your thumbnail violates our Guidelines, your Live may be terminated.