Jimmy Harrop grew up watching Saturday morning cartoons, sprawled on his stomach and doodling away. While he never received formal art training, he parlays this hobby into a festive wonderland for his childhood friend whenever the call comes, and this year he’s turned the windows at Wally’s restaurant into something he definitely is not: the Grinch.

“It’s just something I picked up,” Harrop recalled Monday afternoon, Dec. 8, adding his mother always wanted him to go to art school, but “I’m my…