type by feeding the produced data to a
callback. Can be used when you want to store the image to something
other than a file, such as an in-memory buffer or a socket.
If error is set, FALSE will be returned. Possible errors
include those in the GDK_PIXBUF_ERROR domain and whatever the save
function generates.gdkPixbufSaveToCallback(object, save.func, user.data, type, .errwarn = TRUE)errorGError] return location for error, or NULLgdkPixbufSave for more details. Since 2.4