Are the posters within Portal 2 available as a resource?

I would like a copy of some of the safety signs/posters within Portal. Are they available within the Portal 2 folder somewhere?

Example poster: "Know your paradoxes! In the event of a rogue AI ..."

Solution 1:

While Arda Xi's comment seems to imply that you won't be able to grab them from the game folder, this guy on Reddit and this guy have been uploading hi-res images of the posters somehow(perhaps recreating them themselves?), so if you want them, here are a few:

Also, if you're interested in buying prints of the posters, Valve is selling them in the Valve store: here are the underground posters, the 1940s posters, and the "My boss is a robot".

Solution 2:

Turns out I was wrong. Someone uploaded all of the posters to their imgur account. Here's the link: http://rancidmilkman.imgur.com/all/

Solution 3:

Someone has posted most, if not all, of the Portal 2 posters here: http://imgur.com/a/Xyh4w