This tutorial is using Auto1111 repo but others should be similar.
This is capable of completely transforming your screenshots from that 3d look to photo realism; you can also make it stylized. I will be using my Fallout 4 screenshots as some examples but you could also use it on some 3d renders of characters or drawn art. Use appropriate models for your desired style.
For my settings I use 60 steps, DPM++ Sampling, a resolution of 1920x1080 but you keep it to the aspect ratio of your initial image and a de-noising strength of 0.32 to 0.44. Different Samplers need lower or higher de-noising strengths. For making the prompt I start with deepboru tagger and adjust as needed.
Use appropriate negative embeddings/tags to fix bad iris or other issues. I hope this helps you make some cool images, thanks for reading.
If you want to take SD out of the browser checkout NMKD. It's small, portable self contained app, and you get preview images that are 1:1. One thing that I like about it more than anything else is the ability to copy the entire folder its in and back it up to another drive. Kind of like taking a snapshot of your currently functioning SDGUI. Also, since it's a self contained app, it has everything setup and installed in the SD folder... no need to do separate installs of python and whatnot. Been using it for awhile now.
Anyway, not trying to spam the app, just thought you might like it better then Auto1111 Because in some ways it's day-and-nigh…