SharePoint User Profiles provide a wealth of user data, but one of their most used properties is the profile picture. It can often be useful to be able to access this during custom development, and fortunately Microsoft have made it simple to access the profile picture simply via a URL.
The SharePoint User Profile service application provides a means to offload the traffic on a domain controller when querying information in an Active Directory schema.
When working programmatically with SharePoint you are likely to need to check membership of SharePoint Groups at some point. This article provides a simple route to retrieving user groups information via SharePoint’s web services.