Some of the pictures are factually incorrect. In the case of the flea, it's shoes as in horseshoes, from Leskov's "Levsha" (The Tale of Cross-eyed Lefty from Tula and the Steel Flea). In the case of the worm, you do not kill the worm by eating it - it's the imaginary worm that lives in your stomach and give you stomach ache when you are hungry, so you throw something in your stomach to quieten it.

Idioms are the best. They're culturally essential and usually make no sense to people who are not from that culture -even when explained. I'd love to see idioms from other languages!