This is not bad but it is missing a couple key features. I hope they keep developing it.
First, it doesn't upload to an imgur account, at least as far as I've been able to find. It will upload to imgur, but won't use my account credentials so it's always an anonymous upload.
Second, I can't find a way to repeat the last screenshot. I generate screenshots for videos and documentation and want the exact same image dimensions and placement but at different points as I change things in FreeCAD.
Finally, once the gui is launched, there's no way to take a screenshot with delay. You have to specify it on the command line and then it's the same for every shot.
I've been using HotShots for a year or two. There's things I hate about it and it won't upload to an account either. but it's pretty good in other respects.