What’s going on about selecting a random frame from a video as a thumbnail?

As in the title, what’s going on with selecting a random frame from a video as a thumbnail?

I made a video of the Partial Solar Eclipse, and there is a static picture for the first few seconds. OK, there is a fade-out later, but it’s there anyway. Why does the AstroBin software select a random frame automatically from the middle of the video instead of taking the very first frame? Not to mention the inability to choose a static image as a thumbnail—something YouTube offers—though I won't nitpick about that. Thankfully, it selected a frame with two setups aimed at the Sun; there are also pics showing crowds going to a beach to watch the event. Can I do something with that? A Stargazers Lounge forum shows the very first frame of the YT embedded video; couldn’t it be here as well?

https://app.astrobin.com/i/wubcj9

https://stargazerslounge.com/topic/447556-the-great-partial-solar-eclipse-with-92-at-the-peak/

I didn’t write it in the support section because I don’t know if we can consider it an issue.