Or you could just pop this into the games root folder. The dev posted the fixed files on discord. There is absolutely no need to convert the image files.
1. Nobody said it is necessary. Fact is, all the links provided here lead to versions that still display the same errors : 4 missing images in the introduction scene at the aunt's house because of undefined name.
The only version i know of that doesn't do that and corrects it is at at the devs Subscribestar in the Public Game Builds post. Here :
You must be registered to see the links
(Public Builds \Dominion\Dominion-1.04 Final-dists). This build also doesn't have cousin Stephen and his room in it, though he still gets addressed literally. Leaves the question what will be the final final build...
2. Whether you converted the game or not, the Beta has it's merits. All you need is an appropriate image viewer.
If you navigate to the images folder, you can see some stuff that didn't make it to the game for some reason. Like the older sister fisting in the bathroom. See for yourself, if you don't mind spoilers.