For example, this from Book 4 of Lucretius. There are many similar references to images which are not of the "seeing" variety, but nevertheless impact our minds. I am not saying that I believe this, or that the same phenoma could not be equally explained by stored images in the mind that are agitated when we are dreaming or hallucinating. I don't think it's important that Epicurus explained them "correctly" in our view, but that he suggested natural explanations that take them out of the realm of the supernatural, Theories like this allow us to explain what has happened to us without fearing that they are supernatural:
[26] But since I have taught of what manner are the beginnings of all things, and how, differing in their diverse forms, of their own accord they fly on, spurred by everlasting motion; and in what way each several thing can be created from them; and since I have taught what was the nature of the mind, and whereof composed it grew in due order with the body, and in what way rent asunder it passed back into its first-beginnings: now I will begin to tell you what exceeding nearly concerns this theme, that there are what we call idols of things; which, like films stripped from the outermost body of things, fly forward and backward through the air; and they too when they meet us in waking hours affright our minds, yea, and in sleep too, when we often gaze on wondrous shapes, and the idols of those who have lost the light of day, which in awful wise have often roused us, as we lay languid, from our sleep; lest by chance we should think that souls escape from Acheron, or that shades fly abroad among the living, or that something of us can be left after death, when body alike and the nature of mind have perished and parted asunder into their several first-beginnings. I say then that likenesses of things and their shapes are given off by things from the outermost body of things, which may be called, as it were, films or even rind, because the image bears an appearance and form like to that, whatever it be, from whose body it appears to be shed, ere it wanders abroad. That we may learn from this, however dull be our wits.