Will write a better description later maybe. If you look at my profile you can see I upscale a lot of stuff and info, blah, blah.
Someone had requested this so here it is.

This:
I upscaled textures of Common Clothes with ESRGAN. 

Is this a flawless masterpiece?
No, this is something my computer did while I did stuff because computer smart. Unfortunately, there are overlapping compression artifacts (from multiple savings), so I had difficulty getting a good result on some of the images. I tried a couple times. Since so many people asked I thought I'd give it to you for you to try. 

Kartoffel, does this really need to be 4x?
Sure why not?

Requirements:
Skyrim Special Edition - wow
Common Clothes - as expected

Process:
All textures:   Remove BC1-3 compression with Bc1-smooth2 model.
All textures:   Upscale 4x with interpolated model Manga109 and WeaponsAndArmor @ 0.8.
All textures:   Compress to BC7.

Resolution:
4x:   for body textures is about 4k. hands, feet, head, are about 2k.

Difference of block compression BC1, BC3, and BC7:
In dds texture (the textures skyrim uses), compression via BC1, and BC3 (with alpha), is blocky. Because of this, in original Skyrim, people sometimes leave textures uncompressed. Uncompressed has a big file size. 
With the new block compression, via BC7, it is nearly the same quality as uncompressed, but has the same size as BC1, and BC3. However, this is only supported in Fallout 4 and Skyrim SE.
So even If I do not upscale, by removing BC1-BC3 artifacts and compressing as BC7, the quality is improved.
TLDR: Even without upscale, there is big difference. NO MORE BLOCKY! @400% zoom, so you can see the difference.


Compatibility:
Cannot use with Skyrim Legendary. See "Difference of block compression" above. If you change this BC7 -> uncompressed or BC1, BC3; then, it will work. Use Cathedral Assets Optimizer.

Permissions:
I don't care.

Credits:
FranklinZunge;  Common Clothes
xinntao; ESRGAN
Honh ptsruder; image enhancing utility
Alsa; Models
Game Upscale Discord and Wiki