netzymes,
All I would say is, for starters, to speed up the download of your home page (the most important page of your site), remove all photos from there and perhaps hv links. Then when the user clicks on the links, it takes them to the particular page with photos. Secondly, when on that page, rather than make the user click through each individual image, hv a slideshow instead. Preferably, this slide show should b in AJAX, so while the user is viewing, say, the first 3 images, AJAX is making a call for the next 3. At this point, if the user wants to view a particular image, they can then click on it and view a larger version in a popup.
For a more detailed site review, visit
http://webmastersofafrica.com/webmasters-of-africa-site-review/?nav=sr for more details.
I hope this helps.