Face Painter / Painter's Face

I met this gent this evening on my way home from work. He'd been creating abstract paintings in the street; a lot of the paint was on him, but apparently that was deliberate. Very jolly. Delighted to meet me and my dogs, delighted to pose for a photo, effusive when I dropped some change into his hat.

Perhaps I should've given him more - his jollity raised my spirits, but I'm afraid the money probably does him more harm than good. I'm being patronising. Should I just walk by? Is this photo a form of exploitation?