Early to mid-1960s children’s picture book. Story about some kids (maybe one’s a young teen?) and their friend, a small troll who, I believe, wears a sweater and has a ’60s Beatles haircut. BIGGEST DISTINGUISHING FEATURE: It breaks the fourth wall — they know they’re in a book. Colorful, hip.
This sounds like it might be The Children in The Jungle by Leif Krantz. They paint themselves into an adventure. There is a scene is when they decide they are going to India, and one of them (I think the troll) starts to paint a giraffe, and the kids tell him to move it off to the bottom corner of the page.
Holy cow! That descriptions sounds about right! Amanda, I am in your kid-lit debt! Going to go look for it now.