On the bottom of the main screen in HiLO Lens there are 5 buttons. The left most button is the Camera Roll. If this button is not working it probably means the HiLO Lens app has been denied permission to access the iPhone Camera Roll.
To fix this open Apple's Settings app. Then go to Privacy. Then go to Photos. Find the HiLO Lens app in the list and ensure the switch is On.
If this does not fix the problem please contact us at email@example.com