When building golden images for XenDesktop, most of the time if you are installing the full Online Plugin (or Receiver Enterprise) on the image you would want to assign the XenApp url as a computer configuration so that it becomes the default URL for all users logging in to the desktops of this image. This can be done easily using the commandline for the installation:

C:\CitrixOnlinePluginFull.exe <strong>SERVER_LOCATION</strong>=http://xxxx/pna/config.xml

Or for the latest version Receiver Enterprise:
C:\CitrixReceiverEnterprise.exe <strong>SERVER_LOCATION</strong>=http://xxxx/pna/config.xml

More commandline parameters can be found in the documentations. Alternatively if you have already installed the client, you can change the server location in the registry:

HKLM\Software\Citrix\PNAgent\ServerURL (type REG_SZ)