Texture files, not already associated with a library item, are for optional use in changing or creating props, figures, or hair. The work is done in the "meterials" room, assuming you have Poser5. In Poser4, you use the Render/materials pull down menu on the top left. This is an example of the Materials Room in Poser5 ... it's whole lot more complicated than Poser4. It's best to load an existing prop, go to the materials room and play with what's there to see the effects.

Gordon