“Big picture”

“On thin ice”

In a risky or dangerous situation.

“Big fish in a small pond”

An important person in a small group or limited environment.

“Out of the blue”

Unexpectedly.

“Raining cats and dogs”

Raining very heavily.

“A picture is worth a thousand words”

An image can express more than words.

“Let the cat out of the bag”

To reveal a secret accidentally or intentionally.

“Go the extra mile”

To make extra effort.

“Catch someone red-handed”

To catch someone in the act of doing something wrong.