“The image could not be loaded”

Hi ! First of all, I’m french so please excuse my grammar !

I’m working on a website, where i have the plugin “Justified Gallery” on 4 pages. On each page, the images are loaded properly, but when i click on any image to see it on a viewer, the plugin can’t display the imag and show me the following error message : “The image could not be loaded”.

I tried a few different picture formats, and anything works.

If you have any idea from where it could come, I’ll be glad to have your opinion and your answers about my problem.

Thanks for your help !

The page I need help with: [log in to see the link]