Have you tried with other images?

You could try to change folder's name too.

It worked before when I was advertising sets I had for sale, so idk.

I did try making new folders and just pasting the textures into there and /lp'ing the name of the folder in-game, but it didn't work.

If you want you can send me one of images that don't work and i'll try to put it in custom.

Solved.