Yes, I stand corrected. Right after I hit “post” I realized I don’t really “know”, it just looks as thought it could be likely. It also looks as though he had been to or spent some tme in HI before that photo with the dark boy was taken.
Any tropical location with a beach shack would do, it doesn't have to be Hawaii; although, as you have indicated, it looks familiar to someone who lived there. The child Susan saw was supposedly three weeks of age, the toddler image is one year + so maybe it's a snapshot of a holiday in Florida? I really have no idea.
Does it ever get warm enough in Boston to run around like that?