Product images are not displayed properly

Hi Guys,

As a pre-test I uploaded from virtualhost to my webhost my website, (www.alto-power.com). When i click on a product image, a new large window will open, and close the website navigation. Normally the image should have been displayed on top of the website with the possibility to go trough all images, this is what I want. Images are displayed correctly on my localserver, but not on internet, this is why I do not understand. Could you help ?

Thanks,

Cedric

NB: I am using mystore template, not estore.