I would have thought this to be an issue related to the HTML in the page, rather than a web server one because, as has already been stated, it's not something which is perceived as part of it's function (as far as I know).
Making use of the ALT property in your IMG tag to specify an alternate image to display if the primary one is not available would work just fine. It is more granular in the sense it is based on each individual page, but if you're making use of static HTML templates or better still one of the server side scripting languages to dynamically generate content, it would be flexible and most of all simple
Just my thoughts on this.
Regards.