a gio.OutputStream to save the pixbuf to
name of file format
name of options to set, NULL-terminated
values for named options
optional gio.Cancellable object, NULL to ignore
TRUE if the pixbuf was saved successfully, FALSE if an error was set.
GException on failure.
2.36
Saves pixbuf to an output stream.
Supported file formats are currently "jpeg", "tiff", "png", "ico" or "bmp". See Pixbuf.saveToStream for more details.