Here's how I read Herodotos — all images are "real", because all images are made of particles, and all particles have a source in nature. I read this to mean that we cannot imagine an image that has not been impressed upon or apprehended by us. We cannot apprehend the ultraviolet colors of flowers like bees. Our mind is limited to compatible physical interactions. Like an artist, the mind is not a metaphysical creator, just a creative re-arranger of pre-existing elements loaned from nature.
So, if we can conceive of it, or retrieve it from memory, or play with it in imagination, then the particles must have come from an existing thing (or things) outside of the subjective mind. If you tell me you believe in centaurs, regardless of your fantasy, I know for a fact that you have experienced both the form of a human, and the form of a horse, both of which were real. A centaur is a real, sublimated image in the mind that so happens to not correspond with a tall, chunky creature.
The same is true of individual gods. Mental images of gods exist, like centaurs, as compound unities of particles that travelled from external objects, into the mind, and were sublimated together to form a new image that does not directly correspond 1:1 with an external object. As I read On Piety, the gods only exist in the mind as compounds made from, specifically, [1] the preconception of blessedness, [2] the concept of immortality, [3] the visual form of a human. Now, if you want to name a specific deity, you're expanding on the sublimation. Aphrodite has [4] sex or love (etc.).
This is why Epíkouros writes that the gods are only "reached" through "contemplation". You can't find a god as anything but a mental image or a physical representation crafted by a human artist because you need a human imagination to sublimate together several different concepts. Without the tool of the imagination (or the hand of the visual artist, making the contents of the mind become chunky), the components of a "god-image" are incapable of properly bonding by themselves.