Update User Profile Properties Programmatically
using (SPSite site = new SPSite("http://servername"))
{
ServerContext context = ServerContext.GetContext(site);
UserProfileManager profileManager = new UserProfileManager(context);
string sAccount = "domainname\\username";
UserProfile u = profileManager.GetUserProfile(sAccount);
u[PropertyConstants.PictureURL].Value = "SOME URL";
u.Commit();
}