Can I change a thumbnail on a video?

The best workaround I've found is to replace the automatically generated thumbnail with your own image. After downloading your scorm package, you'll find inside the assets folder the video with your filename along with a .jpg file with the same filename as your video- this the thumbnail. I demonstrate how to replace this easily by exporting an image of your design from Adobe XD, see this other thread. I also do a deep dive into why the thumbnail's color is all screwy yet not everyone seems to experience this 'error' the thumbnail seems be generating a gif/png file with an indexed color mode, yet is being named as a jpg (should be RGB color mode). This is a good way to get unexpected color results across devices and operating systems.