Video thumbnails

I’d like to be able to choose a thumbnail (either a frame from the video, or upload a thumbnail) for an object that has Video fill. Currently Figma uses the first frame of the video as the thumbnail, and if that video starts all black, then the thumbnail is just black. It will show fine in prototype view or mirror once the video starts playing, but when you are editing it would be helpful to see a frame of the actual video so you can adjust properties of elements (e.g. colors, opacities, gradients) and see what they’ll look like composited with video.