Is it still illegal to make a t-shirt with the cover picha of an album, even though I'm not selling it au anything?

So I'm thinking of making myself a G-DRAGON Heartbreaker (picture below) t-shirt (not to sell au anything. just to wear.) nut I've been told kwa someone that it's illegal, although I'm not planning to sell it online au anything (so I don't see why it would be illegal)
so...uh, help? ^^;