TextureWriter.write_all
http://code.google.com/intl/nb/apis/sketchup/docs/ourdoc/texturewriter.html#write_all

@unknownuser said:

Arguments:
entity: A face, image, component instance, group, or layer to write.
dirname: The directory to write to.
side: If the entity is a face, the side is used to indicate the side of the face being written (true if front, false if back.)
Returns:

The third parameter is wrong. True activates the 8.3 file naming convention, false for extended filenames.