I love Topo! maps. As for large-scale image, though, I'm probably not the only one who tried to click on the numbers and wondered why it did something different than I'd been led to expect. It would help if you deleted the A tag from around the big image. Or, an image map would be ideal: clicking on part of the big map would bring you to the corresponding zoomed-in map. See the FAQ for how to do that in HTML.
"So I was sitting in my cubicle today, and I realized, ever since I started working, every single day of my life has been worse than the day before it. So that means that every single day that you see me, that's on the worst day of my life."
--Peter Gibbons (Office Space)