A few thoughts-
When I use google images, I often discover your website. I appreciate your efforts in bringing a very interesting subject to light.
Personally, I am convinced that these images were/are intended to be seen in natural light only, and should be seen at various times of the day e.g. morning, noon, sunset, moonlight (and when fire is made). They should be seen up close and at various distances. They should be seen when saturated with water, partially damp and dry. They should be seen from below, at eye level and from above. And of course they should be slowly turned or placed at different angles during observation (excluding the megaliths).The larger portable effigies will show amazing changes, and will become animated. Natural light, water, shadow and distance (to the observer) brings change/animation
to the rock (which is no longer a rock).
The very act of identifying a rock that appears "ripe" for the artist was/is a fantastically creative effort in itself. The rock calls for the artist more than the artist looks for a rock. A frog's eye, an alligator's eye and an early hominid eye often require that the rock have a lump in the right place so it can be modified for a high ridge eye socket (only in profile unless the viewers focus changes). The complexity and implications are mind blowing.
Ancient peoples did not have a "subject-object" or "subjective-objective" problem. I'm going to stop now, but I recall a statement by William Blake. He observed that we should see through or eyes not with them. And when followed up by Einstein's "imagination is more valuable than knowledge" statement, we can see how most people are blinded by the very methods they use to interpret these effigies.
Anyhow, I've said enough--
Keep up the good work--
“This life's dim windows of the soul
Distorts the heavens from pole to pole
And leads you to believe a lie
When you see with, not through, the eye.”
― William Blake
“Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.”
― Albert Einstein
"... the frequently noted inability (until taught) of non-Western peoples to read photographs shown to them by Western anthropologists is not to be understood as a lack of neurological capacity. Rather, it is based on the absence of a social, cultural, technological, and historical context for understanding and applying the visual logic of photography." Randall White, Prehistoric Art: The Symbolic Journey of Humankind (2003).We take it for granted our relationship to photography is a cultural and technological one. Maybe then we can acquaint ourselves with the cultural and technological drivers of the visual imagery of the past which has been preserved in the permanence of stone.
Like White's "visual logic of photography" a "visual logic of portable rock art" requires developing enough contextual knowledge to be able to apply it successfully. In this way, it is possible for anyone to learn to see portable rock art the way non-Westerners can learn to see photographs.
Portable rock art and proto-sculpture is a knowable, describable and teachable domain. It deserves the deep consideration of the sciences and the humanities and anyone interested in the human condition.
P.S. The below link to a paper by early art and religion scholar James B. Harrod, Ph.D., is among many available at originsnet.org and is a nice way to start developing a visual logic of portable rock art.