How to Edit Thumbnails in Published Videos
If you want to change the thumbnail image in an already-published video, you can do so with just a few clicks. First, open the published video's page in your Vocal Video workspace, then follow the steps below:
Step 1: Select "Edit & Republish" from the dropdown menu.
Step 2: Click on the Thumbnail scene in the scenes sidebar on the left.
Step 3: Edit your thumbnail's text, colors, selected video frame, or upload a custom jpeg/png image with the tools in the Thumbnail side panel. Read this article for more details and some examples.
Step 4: Republish your video.