Custom image templates allows admins to build a custom “golden image” with the added capability to include Azure Virtual Desktop built-in customizations as well as your own customization scripts to install other applications or set of configurations. Leveraging the Azure Image Builder (AIB) service, it takes the elements that you want to include in your build and ships it to the AIB service which builds the image including any additional customizations you have either selected from the Azure Virtual Desktop built-in customizations or those of your own. For more information, read the blog post announcement or the documentation.