The name of the file to identify.
Return location for the width of the image, or %NULL
Return location for the height of the image, or %NULL
Return: A #GdkPixbufFormat describing the image format of the file or %NULL if the image format wasn't recognized. The return value is owned by #GdkPixbuf and should not be freed.
2.4
Parses an image file far enough to determine its format and size.