Its all about the fluff

[Darkwing Duck]

I want a book that is full of great art and myths about Golarian.

It would basically be a book of plot hooks and pictures that I can point to (ie. "the temple facing you looks like this").

If this isn't possible (I know that art can be expensive to publish), then I'd like Paizo to maintain a list of books that its game designers recommend for art inspiration.

A book of myths should be fairly easy to publish.

[Buri]

They do have an "inspired by" list of books. You could look at any art assets made by those authors for ideas.

[Kolokotroni]

I think this would be more appropriate in the campaign setting line as opposed to the rpg line. The RPG line is supposed to be setting neutral. A book of golarion mythis is not setting neutral. And the problem is if you made them setting neutral they probably wouldnt be as interesting or as flavorful.

[Blueluck]

I like Google image search for this.

castle on a cliff
mosque gate
catacombs