After selecting the user from the users' list you can change the profile settings.
There are three subcategories there - Personal Info, Groups, and Security.
From ‘Personal Info’ you can change the user’s names, nickname, email address, language as well as other settings that can be enabled.
In order to remove the photo of the user, so that it doesn’t show in the chat window, you need to untick the “View profile photo” box.
