It’s a better solution than attaching the images even if the attachments work though; geekhack’s forum software / hosting / etc. is never going to have the same amount of time and effort put into serving big image files through a CDN that some dedicated image host will have. Having images hosted somewhere else will keep page load times down, and relieve stress on geekhack's server(s).
Ideally all the images that get posted here would get archived to someone’s backup box [in case the image host site ever goes down or changes hotlink policy or whatever], and then actually hosted from someplace with a beefy reliable CDN capable of handling lots of traffic. (Personally I wish the software would also transparently archive images from transient sources like ebay and rehost those at some kind of dedicated image host, too.) Unfortunately setting something like that up would probably be a bunch of work so it’s probably an unrealistic goal. Instead, people uploading images should just put them somewhere else reliable (imgur, flickr, ...) and hotlink from their forum posts.