Attachment image display issue

[Mupetz]

Hello,

When attached thumbnails images are clicked to enlarge i am getting the direct blank link to the image with some crypted text.
Do you have any idea what this could be ?

Example :

I've installed several mods lately but i don't know which one is causing this.
Please, just tell me what template or part of the code is related to the image display so i can track the bug.
Any opinions are much appreciated.
Thank you