If anyone can give me a solution to speeding up the load times of the thumbnails then i would be very gratefull.Unless you're willing to buy broadband for all of your visitors you can't. You might be able to squeeze a kilobyte or two (maybe even several :D) by compressing your images, but there's little to be done beyond that.
Please be aware that "preloading" doesn't mean "load faster"; it means "load before needed". The idea is that by the time the image is wanted, it's already in the browser cache.
Mike