Have you got the below setting turned on in your Go4 app?
Auto Sync HD Photos: If this setting is enabled then the aircraft will stream full resolution pictures taken from the drone to the mobile device during flight.
Also check out the link below, will give you a better insight on the settings & what they mean/do in the Go4app
You can hook up an external power source to it too, so any USB card reader you have will work - this way you can use it for any type of card not just SD or whatever.
Note that if you do not have a 2017 iPad Pro it will run at USB 2.0 speeds but otherwise functions the same.