User image and name is not getting from roaster -XMPP iOS

I am trying to develop an XMPP chat application for iPhone. This is my first XMPP application, so i have only some basic idea about the the framework. In my application I have a UICollectionView in my home page(I need to display the users listing on a horizontal scroll, so I am using UICollectionView), where I am loading the last chatted users from the XMPPMessageArchiving_Message_CoreDataObject entity. But on that entity there is no user image and name, so I am trying to access it from the XMPPUserCoreDataStorageObject entity using the jidStr.

But at the first time of loading the application, I didn't get the images and names of the users (getting it as null). But when I got a message new message from any of the user, then all the images and names are loading.

Any idea about this issue ?

Thanks in advance