I’ve seen this painting before, in the Boston Museum of Fine Arts. It is huge and the colours are much more vibrant than those seen in this reproduction. I know exactly where this place is – about a 15 minute drive and a 20 minute hike from my house. Beautiful spot.
MATTHEW'S ISLAND 
The part of Maine I know best is the far southern coast, ogunquit, Cape Nedfick, Kennebunk. Relatives had homes there and I would visit as a kid and teen. Such fond memories, although only the very intrepid would actually go swimming! So cold.
I’m up in the Acadia region. But, yeah, the ocean is way too cold to swim in around here thanks to the arctic current coming down via Newfoundland and Nova Scotia. Great for lobsters though!