I decided to write an simple utility to do some basic pixel art scaling using the scale2x algorithm (https://www.scale2x.it/) in C++ and Qt. It will further be used as preprocessing spritesheets for my current game. It works by selecting some input files and afterwards selecting an output directory. There are no optimizations yet and it was not tested thoroughly so there might be major bugs. One known bug for example is leaving an little border around the image.
Please use it on your own responsibility. The build should work on Windows 10 just fine. Download it here.