Hi,
For morning "Coffee Challenge" I created a script that hopefully you can use as a base. It inserts behind the anchor to add the href with a correct http and query string. It's abit brute force with getting the image numbers, but it should work (as long as they stick with 9 digits).
Here's the code.
http://practicewriter.com/vu/?5BF6AThere is an alert in the code to display the built string for testing and confirmation that you can remove when you're satisfied it's doing the job.
Note, the gid= in the http string is the Auctiva customer ID, so you need to replace mine with yours. I've never been 100% sure of what ppid=1122 is or does.
Oh, and if you're using a cache preloader, you might be able to splice this code into that code for both functions. Just make sure it follows the achor for the main image on the page.
Danno
Edit: Here's an update to that prior code that will land you to the correct image on the Supersize page, i.e. if you are on the 3rd image in main, it lands you on the 3rd image on the Supersize page.
http://practicewriter.com/vu/?5C189Note the add of Mouseover function for the image ID switch. You could do that with either the thumbs (part of their Mouseover) or on the main image or both (like Auctiva does).
Let me know if you get it working in an active listing. This method is still brute force with its dependence on the absolute structure on the image URLs, but it works.
Note, it throws errors in the template Preview due to its test images having a different structure. That's why I might decide to work a more general edition for a final widget.
Danno