It could be a depiction of an ogre, or even Malacath. There are also carvings of serpentine dragons and antlered skulls, both symbols of Peryite and Hicrine respectively.
So there is a pair of lorebooks in craglorn that talks about "Four Parents" - and each seems to vaguelly match the images on those ruins (A Dragon of Time, Mother Serpent, the Ox (skull), and Fat Mother) The Fat Mother was also referred to as Orsa in one of those books and it is rather similar enough to word Orsimer. That's somewhat of a speculation, but given that one of the craglorn furnishing items is Ancient Nedic Prayer Wheel, Four-Faced (and having all 4 images there) makes me think its intentional.
Here are lorebooks: