Tangently related question - is it possible to use Bluetooth API to send pictures between devices? I wonder if the bandwidth is too low, or if there any hoops for the user to jump through? Thanks
BLE provides different ways of making requests, it seems the mode with the highest throughputs is when the central (client) subscribes to notifications for a service on a peripheral (server) and the peripheral writes data to the central with or without responses.
Note that it certainly was tested on iOS 6 and iOS 7 has since improved its BLE stack implementation, for instance back then MTU was fixed to 22 bytes while it is now negociated and usually is around 112 bytes between 2 iOS 7 devices (iPhone 5).
I don't have restested to look for the maximum throughput with notification without response but searching the bluetooth mailing list gives this interesting link http://lists.apple.com/archives/bluetooth-dev/2013/Jun/msg00...
Note that it certainly was tested on iOS 6 and iOS 7 has since improved its BLE stack implementation, for instance back then MTU was fixed to 22 bytes while it is now negociated and usually is around 112 bytes between 2 iOS 7 devices (iPhone 5).