I think it can work with .WMV videos but I don't know if there are any restrictions on size or not.
Edit: Found a page that can convert gifs to different video types. https://cloudconvert.com . I had to fiddle with the settings so it wouldn't turn blurry. /u/natezomby
Ever try Krita? It has a lot of more advanced features that might not interest you, but it's configurable and easy to ignore or disable most of them. It's focused on illustration, not editing, so it's designed with that in mind: it comes with some good brushes out-of-the-box, has really simple canvas zoom and rotation, a popup palette for selecting colours and brushes, stuff like that. If you want to avoid all the UI stuff and just focus on the art, you press tab and it hides everything but the canvas and a basic toolbar, so you can just enjoy a screen full of canvas and the popup palette when you need it. (Or you can manually disable everything but layers for similar effect all the time.)
Figured I'd mention it since it's free as well, so even if it only does one thing more than paint.net that you find useful, it could still be worth it.
DarkWire is a Cyberpunk dystopian future based on an alien world colonized by humanity a millennia ago. Over the grinding course of time our knowledge was lost, humanity flung into the depths of the unknown for hundreds of years.
That time of blackness is long over, man rising to take control of his surroundings once more, massive cities sprouting from the dunes and lush forests to protect us from the unknown threats of the planet. Unknown is putting it mildly, Hostile alien life and seemingly magical entities inundate the landscape. Man made horrors from times long past and forgotten plague the ruins of alien superstructures and the dregs of ancient mans first shaking attempts at civilization.
Come check out the first page of the webcomic! https://tapas.io/episode/705209
If you enjoy it, or any of my artwork, consider becoming my patron! Help fund more of this content! https://www.patreon.com/Protocol117
For those of you who aren't aware that Zima Blue was an adaption of [an Alastair Reynolds short story](https://www.amazon.com/Zima-Blue-Alastair-Reynolds/dp/0575084553)... well, now you know. He's a transhumanist hard sci-fi author with a pretty hefty backlog - Zima Blue is a good encapsulation of the kind of stuff he writes.