HL2 graffitis files location

[Cujo]

Posted it on general HL2 discussion but here i guess everybody has finished game and started to play around with game content so here goes my question:
While playing HL2 i noticed bunch uber cool grraffitis on walls. Especially that one with evolution process from ape to combine.
Anybody knows where in GCFs are they located? Couldn't find 'em :/

 

[Cujo]

C'mon guys... Share the knowledge!