To do it without CGi use javascript
1. Put a named div in your document to hold the main enlarged pic
2. Make a layer with a table in it
maybe 4000 wide by 200 deep - or whatever fits however many pics you want
3.put the images in the table link them using <a onclick> to a javascript routine that writes html for the main pic into the named div
and refreshes it.
4. use jscript to float the layer and position it.
5 scroll the layer - either knightrider style slowly back and forth or you can just duplicate a couple of images at the ends and snap back to start
Theres some jscript that handles and moves a floating layer you can nick and modify that runs the menu on my page on
http://kwikfire.com/webmaster-links.htm
Theres some DIV rewrite code you can pinch on my pricing page
http://kwikfire.com/osmium-pricing.html and modify. Its the bit that changes the pricing on the checkout display ... which is itself a sliding layer. Or you could make her dog pictures slide in on a layer the way my 'get advice on this' links do.
If this doesnt make sense to you then give me the problem and for about $40 I will sort it...lol