Android Beam is the NFC based sharing feature introduced in 4.0 Ice Cream Sandwich that allows the sharing of contacts, web links, directions, and other small pieces of information by tapping two NFC equipped devices back to back.
One of the more subtle improvements of Android 4.1 Jelly Bean is the ability to share photos and videos between Android 4.1 devices. Open a photo or video in the Gallery app, and hold your device to the back of another 4.1 device, and you will see the Beam animation, then tap to beam. You will notice that it will instantly initiate a Bluetooth file transfer between the two devices (without the need for pairing beforehand).
Better yet, while in the Gallery app grid view, hold down on image to select multiple files, and use Beam to send entire batches of photos. This was really handy when I needed to send 10 pictures from my Galaxy Nexus phone to the Nexus 7 tablet, to view the images on a bigger screen. All without cables, or an Internet connection. The only drawback is that Bluetooth file transfers aren’t super fast, a 5 Megapixel image takes 10-15 seconds to beam, high definition videos will take considerably longer, obviously.
