My client's seeing something I can't duplicate, Can you check this Web site for me?

I just finished a makeover for GaragePals.com. The item pages allow the site owner to upload a main image and as many as 11 alternate views. The alternate views are supposed to show in a row above the main image, and clicking any one should swap it with the main image. Any image in the main image display should be clickable, and show a near full-page enlargement.

All is working fine for me in IE8 and 9, Firefox and Google Chrome. But my client is finding first one page, then later another where only the thumbnails display, no main image, and the thumbnails won’t show up in the main image window when clicked. He says the problem moves from one page to another now and then, and that when a given page acts up, it does so for quite a while before the issue migrates to some other page instead, and clears up on the previous problem page. That’s pretty strange.

I can’t troubleshoot a problem I can never make show up. I’m wondering if it shows up for others, or just on my client’s machine. Could you take a quick look at
http://www.garagepals.com/base-cabinet-overhead-cabinet-combo-package-deluxe-8-foot.html
and
http://www.garagepals.com/garage-outfitted-with-garage-pals.html
and a few other product pages and let me know if they all work for you, or if you have problems? In either case, whatever you can tell me about the browser, version, operating system and version, and computer might help.

I don’t doubt my client. I am sure he’s really seeing the strange glitch he’s describing to me. I just need to nail down whether it’s something amiss in the JavaScript that manages the image swap, and lots of people hit it, or if it’s a problem on his particular combo of hardware, software and perhaps even a virus or two.

Feel free to post answers or PM me if you prefer.