I don’t want clients or people I share prototype to see the same default Figma project thumbnail all the time.
It would be great if there is a way when sharing the prototype link, Figma caches the first artboard in the prototype and creates thumb. Or, even better, we can choose the prototype thumbnail 
Also, add other metadata like page title instead of default project name 
P.S. Maybe it’s doable, and I’m just not aware of it 