Maybe this thread "Give Us An Example of A God!" should come after examination of "Give Us An Example of A Prolepsis!"
And I think the straightest path to that is going to be to analogize to the eye and the other faculties. In the case of the eye, according to this article the eye receives and processes into a form the brain can handle - in a single word - "light":
(Note: By quoting WIkipedia I am not suggesting that anything was required from modern science that wouldn't basically have occurred to Epicurus. It's an obvious question to ask what part of thinking takes place in the eye and what part takes place in the brain/soul/mind whatever. Also,I am following up on the prior comment that the eye probably doesn't even distinguish borders between separate "things." Picking out one "thing" from another presumably takes place in the brain too.)
Presumably the ears receive and process "sound" into a form the brain can handle. (And it is the mind that can pick music out of background noise.)
So what does the prolepsis faculty receive and process into a form the brain can handle?
I would bet Epicurus would say that it does *not* receive and process "gods" or "justice" or "oxen" or any concrete "thing" or "concept." I suspect he would say that those words ("gods" Justice" and "oxen") are concepts that the mind has formed because the faculty of prolepsis has done some kind of work *beforehand* to allow the brain to think about these concepts. Had the prolepsis faculty not done it's work beforehand, the brain would never have been able to come up with "gods" or "justice" or "oxen" in the first place. Seeing an infinite number of copies of the Mona Lisa would never tell us to pick out the individual things that go into the Mona Lisa out from the background of the painting, unless some faculty of organization of relationships led us to first pick out "things" like hair and eyes and noses and mouths and trees in the first place. Even a gods could not create a world without something which would have allowed them to think of worlds in the first place. (Note that I am writing that carefully because maybe a "god" could take existing matter and refashion it into a "world," but no god could ever make something from nothing or make the universe as a whole.)
It's going to be something more fundamental - like repetitive or repeated "relationships" or "arrangements" - or something else that describes why we should recognize that one body has a special relationship to another body. And the receipt of "images" over time, in which bodies repeatedly appear to us in repetitive relationships to each other, would be a prime candidate to consider as what it is that prolepses "receives and processes."
No doubt someone else can do a lot better than that, but I think that's the direction, and so long as we continue to discuss "concepts" as what prolepsis is receiving and handing over, I don't think we make progress toward giving due credit to either the faculty of prolepsis or the theory of images.
Diogenes Laertius - it seems like I have read commentators explain this word "apperception" in 32 below as a reference to the "repeatability" of the phenomena. Could it be that the "repeatability" of something makes the most difference in justifying us to consider something to be "real" or "true":
[32] Nor is there anything which can refute the sensations. For a similar sensation cannot refute a similar because it is equivalent in validity, nor a dissimilar a dissimilar, for the objects of which they are the criteria are not the same; nor again can reason, for all reason is dependent upon sensations; nor can one sensation refute another, for we attend to them all alike. Again, the fact of apperception confirms the truth of the sensations. And seeing and hearing are as much facts as feeling pain. From this it follows that as regards the imperceptible we must draw inferences from phenomena. For all thoughts have their origin in sensations by means of coincidence and analogy and similarity and combination, reasoning too contributing something. And the visions of the insane and those in dreams are true, for they cause movement, and that which does not exist cannot cause movement.
[51] For the similarity between the things which exist, which we call real and the images received as a likeness of things and produced either in sleep or through some other acts of apprehension on the part of the mind or the other instruments of judgment, could never be, unless there were some effluences of this nature actually brought into contact with our senses.