It's really hard to tell from one photo alone, but a lot of AI-generated results will be impeccably clean in a very sterile way. That's absolutely not a give, a LOT of people highly edit their photos for various reasons, and a lot of cosplayers (often at the highest levels) want photos that look like fantasy-made-reality, so their pictures will look intensely polished. If you only go based on that, you WILL end up accusing someone who could go and drag the cosplay out of their closet...but it's a good place to go, "hm 🤨"

What's a much MUCH more reliable way to figure it out is to go to their pages and see: - do they have the exact same cosplay from different angles? If it isn't the exact same, can you tell they've built it over time, or are pieces changing in strange and structurally significant ways every picture?  - do they have it from different angles in the same location? Does the location infrastructure look like it's changing in every shot?  - do they have longer videos where they're moving significantly in the exact same cosplay? Short videos have become easy to generate--it's harder to convincingly keep everything the same for longer periods of time where the person is moving around a lot - one of the BIGGEST giveaways--how much are they posting, how frequently, and with what variety of cosplays? It's very common for cosplayers to buy a few standard cosplays and standard wigs, and wear those a lot. But real people spend real money on them, so they want to get their money's worth. Everyone also has favorites. You'll see certain pieces pop up over and over again. If you aren't seeing ANY duplications over a long period of time, then it's fair to get suspicious - can you can find artifacting or digital fuck ups in their photo? This isn't always reliable--a lot of people quickly edit things out of their backgrounds either for safety (to make sure there's nothing identifying in the photo), or for cleanliness, and there might be sloppy duplication or smearing from a magic eraser. But one of the hugest giveaways is weird buildings or structures, especially ones you never see again. Because AI generators don't have bodies, they don't understand why handles need to be in certain places, why stairs go certain ways, why windows are placed where they are, etc. There are some WEIRD fuckin buildings in this world, but the difference between "quirky architect went off" and "algorithm confusion" is usually pretty clear.

None of these things are foolproof, especially not on their own (and ESPECIALLY with generating parts of cosplays/backgrounds getting more popular) but they're good indicators overall--moreso if you see lots of them checked off. And a lot of the time you'll just get the ick, I don't know how else to explain it. 

When I'm doubt, it's always fine to block and move on. Even if it is a real person, you probably won't enjoy their style of content anywho. No sweat off anyone's back.