radishwine doesn't share much on his tumblr page other than he is a hobbyist and he didn't have any formal art education.
You can also buy this in a poster form if you want form the artists page zipdraw.com
ZipDraw (or Zip Alegria) is an artist from the United States. You can find more of his art in his deviantart page or his personal website
Don't even trip, dawg.
Matthew J Wills is an artist from New Zealand. You can see more of his art in his deviantart profile.