Wrong image displayed

Hi!
First of all: I love your plug-in, awesome work and exactly what I was looking for! Thank you !

My problem is that when I open an image with the light box (all except the first one of the gallery) and click the next button, the next image is shown, but with the name of the image two steps back.
If I add this image to the cart, the named image (not the one which is displayed) will be added to the cart.

Example:
http://www.marcterrysommer.com/shop/image-store/sky/
Click on image IMG_5208 to open the light box and click next. The correct image will be displayed but the name is the one from the image two steps back (Hawaii, Maui Sunset over Paia instead of Switzerland, Vechigen).

I can reproduce the same error with another freshly installed wordpress theme on the same server.

I installed the store.js you provided to another customer, but with no effect.
Any suggestions?

Best regards,
Marc