I am considering moving my website's images to a separate host (such as imgur) in order to cut down on bandwidth use. Are there any techniques I can use to guarantee that the images will still be shown even if the primary host is down? I am thinking of something along the line of what is possible to do with Javascript, where you can check if the first script tag loaded and dynamically insert another one if it didn't work.
In my particular case the images appear both as regular HTML IMG tags and as background images, with the URLs in CSS stylesheet.