Gets the stock icon name and size being displayed by the Image.
Use get_icon_name instead.
The storage type of the image must be gtk_image_empty or gtk_image_stock (see get_storage_type). The returned string is owned by the Image and should not be freed.
| this |
a Image |
| stock_id |
place to store a stock icon name, or null |
| size |
place to store a stock icon size (IconSize), or null |