If you "lock horns" with somebody you argue with them about something. This photo is from 2-dog-farm on Flickr (reproduced with permission).  It's two cows locking horns over something - probably who should get the juiciest grass.

Home to roost Originally uploaded by waɪ.tiː If something comes home to roost, it means that something you did or said in the past comes back and causes problems for you. For example:- He wrote some stupid things on the forum and now those remarks have come home to roost. It's sometimes used with chickens, […]

Which one is the old goat? Originally uploaded by 2-Dog-Farm If you call someone, "an old goat" you are calling them "an old man" or "a cranky old man". This photo shows my friend's dad, who I'm sure isn't an old goat really, and her old goat Artie.

Let Sleeping Dogs Lie Originally uploaded by waɪ.tiː Let Sleeping Dogs Lie is an idiom that means, leave something alone if it might cause trouble. Of course this is a photo of two dogs sleeping. Sam and Laika having a snooze, with a do not disturb notice between them. It is best to let them […]

Horses Ass! Originally uploaded by judo_dad1953 Calling someone a horse's ass is not very polite. It's an American idiom that means you think someone is obnoxious or stupid. But this photo is of a horse's ass. To be exact: Belgian horse, Belgian Heavy Horse, or Brabant is a horse breed comes from the West-Brabantian region […]