"You can move the image within the limits of the size of the effect."
see the part of the spell description where it says "effect"
also compare with the description of major image
yes, that is true.
I think you are right here actually. I may have goofed on how far I can move the image but ahh well.
Also, I only "give up" if my questions are answered. If they are not going to be then I do not declare defeat. Though I don't think it matters much at this point.
And yes I was expecting solid fog to make him drop. Since it did not the bats were going to take care of things (always another way). I could always solid fog him again if things got hairy. He wasn't that much faster than my hippogriff that I couldn't keep with the cloud tactics (had two scrolls of it for just such a sticky situation). Also he's wrong. On the ground a medium creature can be attacked by up to 8 creatures. So too for a large creature vs large creatures (even without reach that's just if they are adjacent). Remember diagnolly the first square is 5ft. In the air that number increases by 18 because of 3 available dimensions to attack from. I can have up to 26 large creatures with no reach attacking a single large creature in the ait by forming a cube around that creature.
I don't know about the diameter thing I probably would've ruled that it expanded in the air myself but there ya go.