An image slide-show solution dilemma!

Greetings,

I'm trying to come up with the best web-design or web-development solution for an image slide-show. The dilemma here is that I want this slide-show to be a good user experience for both: broadband visitors and 56k modem visitors. So, yes, I want the broadband user to be able to click "next", for instance, and the next picture would literally instantly appear, no waiting for downloading at all. On the other hand, I don't want to clog the bandwidth of the poor 56k modem visitor, unless....he or she gives permission! Meaning, I'd like to give the visitor, any visitor, the ability to tick or mark a certain square of a mini-form, which can say something like "Download all pictures for faster viewing". And if the visitor has ticked that square, then the slide-show will try to download all the pictures as fast as possible, while the visitor is viewing the first few pictures, one by one. Otherwise, the visitor will load each picture individually after he or she clicks "next". How do I do something like this? With and without Flash? Thanks a million for anyone taking the time to help.

I might suggest doing two versions of the site. One with Javascript image preloads. One without. Give the user an option on the first slide or intro page.

Doug:~