Why would you want a mirror, and especially why would you want a mirror on an ephemeral image hosting site? The XKCD site has been online since '06 and is already archived on archive.is and web.archive.org, imgur has been online for less than that time and certainly can't boast the same amount of uptime.
Yes but surely imgur is more prone to that, given its more lucrative surface area? And either way, wouldn't archive.is or web.archive.org be a better choice, given that both have big infrastructural systems that are very literally designed from the ground up to avoid data loss?
