One solution to this problem is to host the image yourself. That's what I do when I want to use an image on this blog. I have an account on flickr, which is a terrific, and free, image sharing site, so I download the image I want to my computer, upload it to flickr, then get the necessary address from flickr for the image. That way, any bandwidth pulled for the image is my responsibility.
Let's say you want to use an image at
http://www.foo.com/bar/image.jpgInstead, use a modified URL with an address that actually points to PlanetLab by inserting a change in the address
http://www.foo.com.nyud.net:8090/bar/image.jpgViolá! Folks will now pull the image from the generous folks at PlanetLab, rather than from foo.com.
Ben93 has a tip for using this:
It helps to preview the posting before you hit post as this gets the caching service to do the initial fetch of the picture, which can be slow, before your posting appears to the public. Sometimes you need to wait a few minutes and re-preview it before everything will appear as it should, and some web servers will not play ball with the cache, and this is how you weed those out.Of course, before long Google is going to host everything on their Big Server Farm in the Sky, so this problem will go away ...