yeah, all the time.

its become a part of my routine. render, save as jpeg. open in photoshop, uncheck pixel aspect yada yada...annoying. and you get that dialogue pop up ...' pixel yada yada is for preview purposes only' or something.

it makes it hard when i want to combine renders. which i know ( hammer.horror) is a crazy way to be going about things, but mental ray crashes on me when i try to render out big images, say 8000 by 5000. im just experimenting really.