Where to find the generic texture files, e.g. Asphalt_New.jpg

I am writing one exporter. I got trouble to find out the generic texture pictures, e.g. Asphalt_New.jpg.
For the above generic texture, I mean the case when SUTextureWriterLoadFace(tw, face, &front_id, &back_id) returns SU_ERROR_GENERIC.
I used tt_su’s sample codes to get the texture path. Who knows how to get this kind of texture pictures on disk?

I searched my whole disk and could not find it.

Figured out. Now using SUTextureWriteToFile to solve the problem. No need any more.