Delve show profile img bt PictureUrl property is Null? Why?

Question

I have to display all SharePoint Online user's profile information including profile picture on a page in SharePoint Online.

Here profile pictures are added in Azure Active Directory.

As mentioned http://blog.atwork.at/post/2014/06/14/SharePoint-Online-UserProfiles-and-the-story-about-synchronizing-with-Azure-Active-Directory, `PictureUrl` property does not synchronize with Azure Active Directory.

But, When I open up the delv of user, the profile picture shown there, but when I try to fetch the user profile using REST API, `PictureUrl` propery is always null?

 

 

 

PictureUrl property:

 

 

 

Any reason behind this?