So I've been using windows and playing a lot of Soldat recently, and I've also taken a fond liking to cygwin (fake unix on windows). The screenshot converter program I've been using for years kinda sucks and dies after a few images (I don't know the name of it but it comes with a file called corona.dll or something similar)
So yeah, I took the liberty to devise a crafty little customizable perl script that does multiple images at once, via threading. It requires perl's imagemagick api.
I've only tested it on cygwin/windows but I'm sure it'll work on linux/unix and possibly even strawberry perl (perl windows, I think).
Usage: save it to the Screens folder and run it in a terminal and watch it convert lots of images quickly.
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