I thought that spent a while thinking which image he meant
Judging by his src attribute it looks like he might be pulling the image from a database or definitely another source. And his href of where the image leads to is a directory.
I'm not totally sure of your cause but maybe check the image name in the 'href' against the image name which loads up in the lightbox.(which i'm sure it must be declared somewhere else)..
Regards,
LC.