I dont know if this is possible, but you could try to make the images larger (say to fit 1600x1200), then make each image/frame/etc, some kind of variable.
When the user comes to the site, you determine their resolution, and have the browser resize the images/frames/etc.
(eg: if resolution = 800x600 then
title.width = 400
title.height = 150)
Again I dont know if its possible, but it might because I know you can cange the display height and width of an image with standard HTML tags.