In reply to Deepak Gupta.

Yes, you're right! I've updated quickly the post with the following:

To add in your own spheres, visit maps.google.com, search for a location and click "Add Photo". After the photo has been added or to access a previously submitted one, visit Google Maps and choose the "My Contributions" link in the left popup navigation menu. Then, choose Photos, and click on your uploaded photosphere. It'll load and at the upper-right, click on the three dot menu button to select the Share or Embed Image option.