I'm sure its a coincidence as his render is a clean copy and yours in behind effects, so theres no way he cut the image out. so he just found the render and used it, maybe without knowledge I dont know, so maybe technically he did make it.

And of course neither one of you created the render so you really cant say you made it 100%, I'd say put it together more like it

Did you have the render posted somewhere that he could have seen and used it?

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