Popup image window often doesn't open

[Jiri Loos]

On my gallery often happens that after clicking on med-res picture popup image window doesn't open. It happens very irregulary, but it most often doesn't work.  Does anybody have any idea about the cause? Coud it be caused by the server (any timeout issue), my internet connection (legs) or bz anzthing else? Are there any means to prevent the issue? Can I somehow set anything in the code of javascript displaying the window, php code? Any help graeatly welkomed.

The gallery is here: http://galerie.artavision.cz

[Nibbler]

All seems ok to me, only pic that doesn't open is too small to have been resized in the first place.Can you link to a specific pic that exhibits this issue ?

[Jiri Loos]

There is no specific picture that is not being displyed, sometimes it happens to me that a picture doesn't work and when I go to another one and return back, it workes then.