Every time you post an image on the Internet, you grant a license for people to make copies of it. Facebook, Instagram, I'm sure DeviantArt and any other site that hosts images has language to this effect in their terms and conditions. It is necessary for a copy to be made in order to transmit the image to a client for anyone to view it. If Stable Diffusion and Midjourney viewing the images is a violation of copyright, then so is Google Image search and everyone with a web browser viewing any non-public domain image on the Internet.