With regards to the "wallpapers" sites.
I figured out this kind of theft comes generally from sites outside EU that utilize the API of Instagram.
So once I deleted my public profile there, all that disappeared.

Funny how if you try downloading images from Instagram, they are in low resolution and high JPEG compression, but through the IG API everybody has access to the original content. It was like that back then at the time I deleted my account there. I wrote several times to the Instagram legal team, nobody gave a fuck. So I did that same in return. I don't need them.