AI images are often not labeled regardless of whether they're trying to mimic real life or mimic art. Someone who knowingly posts AI images is lying to you about who made the image, it's specially worse when they're unlabeled

A piece of art and an AI-generated image are two very different things that can often look the same, because that's what generative AI is made for: mimicking what humans make, a computer lying about its identity as a computer, and pretending to be human. Every AI image is a lie.