If you search around for Acadias posts you will find a giant newbie guide she has posted that tell you alot.

You should create an "external" runtime.  And keep all your added content there.

Inside poses are also most of posers textures.  it goes

Runtime
Libraries , geometries, textures

The libraries folder contains many subfolders- the same that you see in the far right column in poser.

The geometries folder contains .objs
The textures folder will contain alot of jpg

INside libraries there is another folder called Materials > this has lots of texture files too but a different type I think.

That's what I have figured out so far - hopefully someone else more knowledgeable responds as well.

I am:  aka Velocity3d