is it possible to have the tool iterate through every combination and output images for every combination? Should be a simple implementation to have it step once, export, step again, export and so on. It would generate a lot of data, but would be a useful option. I'm willing to pay for implementation of that sort.
tldr: Doable, but the best is to just port the whole thing into your game. Drop me an email if you wanna help.
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This would generate GBs of data; some of the files would be identical as other ones (e.g. when eyes are covered their colour is not relevant) but checking that would be quite time consuming (O(n²), although if you spend some time on it it could actually be a bunch of ifs so maybe not).
The problem (not a big one) is the platform really. In a browser I cannot cause it to export without your interaction (click - it's made that way so a random website you visit don't push data to your Downloads directory). So I'd have to generate all of them in memory and then push to you but it would require a lot of memory (even more then the output files) - your browser would crash sooner then it's finished. This could be done in batches I guess, I imagine it's not perfect.
I could go with Electron. It would let me to avoid browsers' safety rules (afaik, not 100% sure). Tbh I just don't feel like touching this stuff atm :/; The code that is uploaded right now is minified but the variable names are not shorten (and it's not like there was much comments anyway) so you can unminify it and give it a try. There shouldn't be much changes needed; but it would require learning about Electron.
Finally there is an option to just create a command line version of the tool (I find them easier to include them into your pipeline). Shouldn't take much time but I don't really know if this is what you'd like to use; nor if it'd be useful for anyone else.
That being said: are you sure that you want to ship your game with such an amount of data? If your use-case is "I want a few millions of different characters" than I'd suggest porting the generator to you game and just spawn enemies as you need them during runtime. Your game would be way (WAAAAY) smaller and you'll gain flexibility (removing/adding elements, changing probability of some of them, changing/adding colour-scheme, removing this stupid pirate hat you don't like, making blue-skin enemies resistant to ice-gun, generating procedurally names of the enemies, etc, etc...) and it's not like it's difficult (also fun imo). I'm happy to walk you through or answer any questions about the code over the email or skype if you'd like that - you can drop me an email.
Also, addressing your willingness to pay me money - while appreciated, I'd be happier if you make a fine game.
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huh, so much typing, sorry for that XD