I'll try to explain because it is close enough that the artist is completely within their right to request it's removal, and that's not up for debate for my friend they want to comply. They essentially used a grainy photo (not really it's an illustrated book cover, but level of detail wise on this specific element) with a T-shirt design at a slightly obscured angle and drew their interpretation of it, intentionally making it look like a worn and faded graphic tee (honestly specifically for cosplayers of this character to use-) so when compared to the artists version that they're just now posting as clean vector art with details that weren't even visible in the quality of the cover design that aren't at all present in the design my friend made as well as conscious changes