[Zope] Newbie question: http-cache, caching elements

hi, does anyone know how to cache objects like gifs by a http-cache? my problem is that i have a navigation (constructed via tables) that is set up and changes dynamically every time a link is hit. this table includes a small picture. i think with the standard http-cache i can only cache "finished" html sites. therefore the picture is loaded every time i click on links that have not been clicked on before. i would like to cache this special element explicetly. can it be done? thanks a lot, fernando