What is the difference between a metaphor and a simili?

A simile is explicit, using "like" or "as" comparing two things.

A metaphor is implicit saying one thing is another or implying it is.

My dog eats what we drop like a vacuum cleaner. - Simile

My dog is the dining room vacuum cleaner. - Metaphor

My phone is as loud as an orchestra. - Simile

My phone is an orchestra. - Metaphor

Her cries and tears are like a thunderstorm. Simile

Her thunderstorm crying is unbearable. Metaphor 

Both should cause pictures in your head and are comparing things not normally considered similar.