Imagery is the use of sensory details to allow the audience to imagine what is being described. Some examples are:
"___ smells like ___"
"___ looks like ___"
"___ feels like___"
And so on. Sensory details are not always similes either. They can be something such as, "After John hit me, I could feel the anger rush through my veins as I get back up to throw a powerful punch back at him."
The anger rushing through the speaker's veins is a sensory detail. It's describing how much adrenaline is rushing through their body and how angry they feel after John hit them.
I hope this helps!