the use of reading glasses (which come in various diopters) do make the image seen inside a scope easier to focus on, but i doubt the image is really bigger.
i have two different power reading glasses at home, one for computer distance, and one for close, hand-held reading. i'll look through them (into the scope) tonight and see what i can see (so to speak)
i think i have some clip on magnifiers somewhere, or one of those visor type magnifiers, and i'll hope to find them and try them tonight, and let y'all know (southern collective).
if there really is a magnifying effect, then it would affect the 12x power setting, and an HFT shooter might have to set the power to 10 or 11 to make it equal to 12, however i don't think that's the case.
my reason for thinking it won't happen is that scope magnifiers cost a whole shipload of money, and if you could get the same effect by wearing dollar store reading glasses, those people would be out of business.
i also have one of those air force resolution charts fastened to my indoor target, and i can compare target resolution (based on my eyes) using both long-distance glasses and reading glasses.