In this screenshot you can see a man standing behind a wall.
The wall has a transparent GIF on both sides.
In the preview window the wall is black.
In the photo the wall is invisible.

Transparency works only when taking a photo in Q3 or Q4.
It doesn´t work in the preview window, or with Q1 and Q2 when making a photo.

It has never been possible to set or change transparency within SH3D.

Sorry, no photo here, please follow this link.

Hans