Agreed, but this latest image shows an actual painted scene. The ampule room is like the Sistine Chapel. A Giger Sistine Chapel... oh shit... wow... I just wet myself. 
Mee too...!!

Tried to enlighten the creature a bit...

Looks similar to the one from the cavepainting... and the engineers helmet to its right, with one visible eyesocket...
Could these 'active murals' depict the engineers lifecycle and their creative biomechanoid 'capabilities', just like some of the murals Giger did for Alien that never made it into the final film, because the whole idea of the temple was scrapped?