Picasso is credited with saying “Good artists borrow; great artists steal.”
T.S. Elliot is also credited, as is Stravinsky.
Who really originated it?
Maybe they all said it…?
Irony is the lowest form of humour and whatnot.
They all stole it from me:D
In any case, isn’t it
“Good artists copy, great artists steal”?
Well. That wasn’t helpful.
Then there’s “Real artists ship,” from Steven P. Jobs.
Dunno if he stole it from anyone, but odds are good Bill Gates stole it from him. 
If you type “good artists copy, great artists steal” into Google, all the relevant sites say Picasso. If you substitute “borrow” you get fewer hits but they still say Picasso. Don’t see any other options.