Henra - did you have to register to access the images? Clicking on them just brings up a registration page in German.
Flying up the canyon which is more or less north-south oriented and open to the north, (narrowing towards the south) was the first location suggested near the beginning of the thread and from recent communications may be the site. There are two sites which can look like the photographs - the one from the west > east, and the one up the valley - with (obviously) different peaks in the background.
It's still a puzzle...