Using Fotorama on this theme is not the answer because of its cropping problem. Vertical photos seen on a horizontal screen are badly cropped – you can see only the middle part of them which makes it impossible to see vertical photos on a desktop or laptop computer.
Anyway, flexslider crops correctly but the bug makes it difficult to use on a mobile.
Also, the problem with double click and the black screen is not only on iOS devices but on Android based mobiles as well.
I bought this theme only for the responsive portfolio but its responsiveness is faulty and needs to be corrected.