Developer Pictures
In some of the Jak and Daxter games, there are hidden pictures of the game developers.
Jak and Daxter: The Precursor Legacy
In Jak and Daxter: The Precursor Legacy, there is a texture file called fin-leafygroundBACKdirt.png
in the finalboss-vis-tfrag<,/code> textures folder which contains a hidden face baked into the image. The texture repeatedly appears in the mountainous landscape surrounding the dark eco silo at the final boss fight. It is difficult to see during the final boss fight since everything is dark and purple, but it is easily viewable from the silo after completing the boss fight and the weather becomes clear again.
Jak II
Jak 3