That is true. I was also concerned about not overloading it or causing Veks any headaches, but I imagine the alternative (hotlinking and getting virus or other dirt on E) would be much worse. The Wiki, it is.
Four sites that are pretty safe to use (if I'm remembering right), if you are not using the Wiki, are Imgur, Pinterest, Tumblr, and Photobucket. These four, to my knowledge, aren't headache-inducing and don't typically need worried about because they are pretty much made for hotlinking, as Veks mentioned about Imgur above, for example.
Wiki is pretty much a must-have if you want animated gif avis or sig images, though.