To use airdrop you need to turn on wifi and turn on bluetooth, I usually turn on both but maybe only 1 is needed, I'm not sure, but just turn on both in settings.
Swipe up from bottom, tap airdrop, then choose everyone so it will show you all iphones within reach. Do this on both phones. Then you can go into photos, tap select and in the bottom left tap the icon with the arrow pointing up and you will see the airdrop section. Your friends name should appear there if bluetooth and wifi are on, tap airdrop, then they get a message to accept, and they get the image. It works really slick.