this is maybe not good advice, because it breaks the spirit of your college's (arguably foolish) policy, but it would almost certainly be successful. Register XYZ as a domain name, pay the very small cost to host XYZ at, for example, Dreamhost, or many of the other cheap (<$100/year) hosting services. In their hosting, you need have nothing but a .htaccess file, which redirects requests (either all requests, or just certain directories, e.g. /MathOverflow/ in your case) to your preferred actual hosting, e.g. in your case at csail. It's very unlikely that your system administrators will ever notice that you've done this, or complain about it, and it achieves both your goals --- a stable URL that you have complete control over, combined with hosting conveniently managed by your local sysadmins.
(If the technical details of what I suggested don't make sense, I'm happy to try to explain further, if you're interested.)
best, Scott
]]>Of course this problem will disappear if we ever move to SE2, because one uploads the images in a post and they are from then on maintained by Stack Exchange.
]]>See also my earlier worry: The impermance of images on MO (in which, incidentally, I misspelled "impermanence"!).
]]>Alternative advice welcomed!
]]>Is there a way to edit a question/answer without having it get bumped to the front page?
]]>