How to change the thumbnails on your YouTube Shorts

1. Download the official YouTube app on your mobile. (Not the YouTube Studio App, although that has other features.) 2. Open the YouTube app. 3. Go to your list of Shorts. 4. Notice on the right side of each short video there's a 3-dot menu you can click on. 5. Click on any of them, then click "Edit" (not the "Edit in YouTube Studio button) 6. Now you'll see your thumbnail on the top left -- click on the pencil icon. 7. Tap and scroll through the video to select a thumbnail.