Using custom links in portfolio creates double entries

HI,
I try to use custom links with portfolio items because it opens lightbox who are really filling the screen, if I don’t use custom links the lightbox seems to be opened with a fixed size ( and a too small one …), BUT when using custom links it creates double entries : each image in the lightbox are duplicated lets see the example page : 2 pictures in the grid but 4 in the lightbox : http://lepixelstudio.com/test2/
Pleeeeaase help !