Saving RGB or Grayscale images from GdkPixBuf

[Michal Porzuczek <mporzuczek gmail com>]

Hi

I was wondering if gdk_pixbuf_save supports saving RGB or Grayscale
images. I have attempted to use the add_if_writiable function that is
specified in the api reference but I just get gibberish so I don't
think I'm doing it right.

I have tried to save RGBs  by making the type "RGB"but not knowing the
rest of the parameters I just set them to NULL and I do have an "RGB"
file appearing where I tell it to save but unfortunately no actual
data is being saved and I was wondering what these additional
parameters are and if it is possible to save it in grayscale.

Furthermore, I was interested if there may be an even faster way to
save images, speed is the primary objective with the image saving.

Thanks a lot,

Michal