As we near Midsummer, I have pulled out Shaun Tan's Rules of Summer and read it two or three times in the past week. At each reading, I've laughed out loud. It's brilliant! It's zany! It's surreal! It's wise. For me, it's one of the indispensable books.
On his website page at the link above, Tan offers commentary on each of the paintings from Rules of Summer with the caveat that maybe he shouldn't, that maybe he should leave it up to readers to find their own stories in the pictures. Of course. you can do both: Read what he has to say and then use one of the images to inspire a short story or flash fiction (or vice versa).
Personally, I don't want to explain Tan's sublime intimations. I had a teacher once who claimed you didn't understand something unless you could put it into words. Ha! Rule of summer: Never take teachers too seriously.