Inspect cached images located on the file system. Input an assetId and press search. It will now look though the file system and list all cached images for that id. You have to option to clear a specific image cached or clear all images for the assetId.
You also have the option to send out an event to all CD servers, telling them to clear their image caches for a specific assetId.
To enable the event on the CD Server, locate the following file \App_Config\Include\damforsitecore\DFS.Connect.config. Open it and find the tag events. By default the event name publish:dfsClearCache:remote will be commented out. Remove the commenting to enable this custom event.
