When you use get_serving_url, it creates a url for serving the image. However, according to http://ikaisays.com/2010/09/08/gwt-blobstore-the-new-high-performance-image-serving-api-and-cute-dogs-on-office-chairs/
Deleting an image blob doesn’t delete the image being served from the URL right away – that image will still be available for some time
If I get a DMCA takedown notice for the image, it's important to remove access right away. So is there a way I can remove access quickly?