In an effort to reconcile (DL 10.32) "All concepts have arisen from the senses" with (DND 1.43) "...gods exist, because nature herself has impressed a notion of them on the minds of all." I am thinking:
What has "nature used to impress a notion of gods on our minds" if not the very images of the gods that come from their bodies?
We also cannot forget that Philodemus discusses the actual physical processes by which the gods exist:
Philódēmos, On Piety, 1.8.205: [Obbink] And having written another book On Holiness, in it too he makes clear that –not only that thing which exists indestructibly – but also (that which) continually exists in perfection as one and the same entity: are termed in the common usage "[unified] entities" – some of which [entities] are perfected out of the same elements, and others from similar elements.
Philódēmos, On Piety, 1.13.347: [Obbink] Its constitution out of things similar would obviously be a unified entity: for it is possible [for beings constituted] out of similarity for ever to have perfect happiness – since [unified] entities can be formed no less out of identical than out of similar elements ([and both kinds of entity] are recognized by Epicurus as [being] exactly the same things, for example in his book On Holiness.)
Philódēmos, On Piety, 1.13.364: [Obbink] ...Therefore he was wont to say that nature brought all these things to completion alike – and that for the most part many things come about [when they are formed] from an aggregation of various similar particles…
Sedley is correct when he says "each of us has an innate propensity to imagine." We also have an innate ability to see -- but we have to actually look and see things to use that ability! So he goes too far by saying "By doing so, we are ipso facto giving a concrete realization to the prolepsis of god." We can give similar mental "realizations" to centaurs. The process Sedley is describing is actually how we form a hypolepsis (supposition) and unless it corresponds to an external body, it is an empty thought.