/Mount-Wim /WimFile: {/Index: | /Name: } /MountDir: /readonly Mounts the WIM file to the specified directory so that it is ...

/Mount-Wim /WimFile: 
  {/Index: | /Name:} 
  /MountDir: [/readonly] 

  Mounts the WIM file to the specified directory so that it is available for 
  servicing. 
  Use /ReadOnly to set the mounted image to have read-only permissions. 

    Examples: 
      DISM.exe /Mount-Wim /WimFile:C:	est\images\myimage.wim /index:1 
        /MountDir:C:	est\offline 

      DISM.exe /Mount-Wim /WimFile:C:	est\images\myimage.wim /index:1 
        /MountDir:C:	est\offline /ReadOnly