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

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