Img2img isn't always spot-on with what you want it to do, though. I was making extra pictures for my kid's bedtime books that we made together and it was really hit or miss. I've even goofed around with my own pictures to turn myself into various characters and it doesn't work out like you want it to much of the time. I can imagine it's the same when going for porn, where you'd need to do numerous iterations and tweaking over and over to get the right look/facsimile. There are tools/SD plugins like Roop which does make transferring over faces with img2img easier and more reliable, but even then it's still not perfect. I haven't messed around with it in several months, so maybe it's better and easier now.