you can use arc_unpacker found on github
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Edit coz I feel like helping:
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1. move arc_unpacker.exe and the subfolder "etc" to your game folder, rename the SlutTrainer (ENF)v5.exe to SlutTrainerv5.exe (we don't want brackets or spacebars in our names)
2. make and run a .bat file in game dir including this code:
arc_unpacker --dec=microsoft/exe SlutTrainerv5.exe
3. open the new SlutTrainerv5~.exe folder in your game directory and extract extra_data with winrar
(7z or winzip might work too) this gives you all gamefiles, including the CGs!
It should be possible to extract everything without a bat-file via drag and drop the .exe on arc_unpacker.exe too... this method can take very long tho as it will try to detect the decoders.
The first method should save you some time and is therefore recommended.