We have several other interesting conversations going on right now but here is something that may ultimately be related that I think deserves a separate thread:
In Epicurean theory, what is the relationship, if any, between"images" and "thoughts"?
It seems to me that in Book Four and other places in Lucretius, there is a close relationship between the impact of images on the mind and then the operation of the mind in forming a picture of what it wants to think or do.
Book 4 of Lucretius:
 Next, how it comes to pass that we are able to plant our steps forward, when we wish, how it is granted us to move our limbs in diverse ways, and what force is wont to thrust forward this great bulk of our body, I will tell: do you hearken to my words. I say that first of all idols of walking fall upon our mind, and strike the mind, as we have said before. Then comes the will; for indeed no one begins to do anything, ere the mind has seen beforehand what it will do, and inasmuch as it sees this beforehand, an image of the thing is formed. And so, when the mind stirs itself so that it wishes to start and step forward, it straightway strikes the force of soul which is spread abroad in the whole body throughout limbs and frame. And that is easy to do, since it is held in union with it. Then the soul goes on and strikes the body, and so little by little the whole mass is thrust forward and set in movement. Moreover, at such times the body too becomes rarefied, and air (as indeed it needs must do, since it is always quick to move), comes through the opened spaces, and pierces through the passages in abundance, and so it is scattered to all the tiny parts of the body. Here then it is brought about by two causes acting severally, that the body, like a ship, is borne on by sails and wind.
Another example that is outside the core material but which may shed light on the question is Cicero's question to Cassius:
[15.16] Cicero to Cassius
[Rome, January, 45 B.C.]
L I expect you must be just a little ashamed of yourself now that this is the third letter that has caught you before you have sent me a single leaf or even a line. But I am not pressing you, for I shall look forward to, or rather insist upon, a longer letter. As for myself, if I always had somebody to trust with them, I should send you as many as three an hour. For it somehow happens, that whenever I write anything to you, you seem to be at my very elbow; and that, not by way of visions of images, as your new friends term them, who believe that even mental visions are conjured up by what Catius calls spectres (for let me remind you that Catius the Insubrian, an Epicurean, who died lately, gives the name of spectres to what the famous Gargettian [Epicurus], and long before that Democritus, called images).
2 But, even supposing that the eye can be struck by these spectres because they run up against it quite of their own accord, how the mind can be so struck is more than I can see. It will be your duty to explain to me, when you arrive here safe and sound, whether the spectre of you is at my command to come up as soon as the whim has taken me to think about you - and not only about you, who always occupy my inmost heart, but suppose I begin thinking about the Isle of Britain, will the image of that wing its way to my consciousness?
I will see what other cites I can come up with to use for discussion, but has anyone got any thoughts (no pun intended) on this relationship?
Part of the reason I am asking this question is to try to get a better handle on the pleasure and pain that is involved in making the "mental" vs "bodily" distinction. Are mental pains and pleasures felt as a kind of "touch"? If so, to what extent are images involved?