This seems reasonable to me, though I'm a little wary of drawing the line so firmly just in case there's a case I'm not thinking of where sexual image would best illustrate something on a non-sexual page.
-Fluff
Yep, try http://commons.wikimedia.org/wiki/Category:People_using_vacuum_cleaners
So do we all agree that the Principle of Least Astonishment needs to be encoded into some kind of policy or guideline? In other words, images with a sexual context should only appear in articles/categories that also have a sexual context.
Ryan Kaldari