I know this is about two years old now but I found something that looks like it could solve everyone’s problems:
Works pretty well on Linux and I have no reason to believe it wouldn’t work anywhere else. I used this to upscale a photo of my parents from when they started dating as a Christmas gift.
Thanks for sharing.
I’m not sure if any of the models have been trained with real photos. I have done some tests with realesrgan-x4plus and for general photography it works quite well. But photos with a lot of details, for example nature with animals, the result is somewhat washed out and it loses many details. I will continue investigating.