Why can i see hidden image with a polarized spec?

[crays]

Hi, i can't find any article related to this question, i went to a spectacle shop, they claim their spectacle are polarized, i tested it by diagonally aligned the spectacles and yes it is polarized, but then sales man asked me to put on the spec and have a look at a picture.

First it was just a fisherman with a rod but with my spec i can see a fisherman with a rod and a fish. I wonder how this happens? Anyone could answer me pls? Thanks.

 

[Phrak]

Perhaps the picture was covered in polarizing film, oriented differently for the fish.