Imagery is everywhere in Shakespeare: open your play at any page, and there'll be something interesting there which deepens or makes more complex the meaning of the passage.
Once more unto the breach, dear friends, once more,
Or close the wall up with our English dead.
In peace there's nothing so becomes a man
As modest stillness and humility;
But when the blast of war blows in our ears,
Then imitate the action of the tiger;
Stiffen the sinews, summon up the blood,
Disguise fair nature with hard-favour'd rage...
This very famous example is usually talked about as a jingoistic, bloodthirsty call to arms; a patriotic speech from the King to his loyal soldiers. Yet, a closer glance at some of the imagery suggests another layer of meaning within the speech.
Note the number of duplicities that Henry incites his men to perform: "disguise fair nature with hard-favoured rage", "imitate the action of the tigers", "lend the eye a terrible aspect", and so on. What's the difference between asking someone to act like a tiger, and be like a tiger?
Well, Henry seems to be acknowledging that the bravery and courage summoned up will be faked, acted, performed, rather than real. What then, is usually read as jingoistic, is revealed as far more desperate: Henry knows that his men don't want to return to the battle, but he tries to help them to physically perform bravery even if they feel terrified. And all that comes from the imagery!