Make it so you can add a thumbnail for videos uploaded. I had to do it directly through Facebook and LinkedIn 
I’ve just stumbled over the exact thing. It’s very bad for performance when the video is just white before it starts playing – I hope this can be fixed, maybe with a preview image or keyframe if not a thumbnail.
Yes! When uploading in a video in the platform natively or through Sprout, I can compose the post and add both the video and video thumbnail in one fell swoop. It appears that the only way to do this in HubSpot’s social tool is to upload the file, then go to the file to edit to add the thumbnail, and then go back to the social composer to create the post. This is very inefficient and impractical.