Put an enlarged view of this excellent painting on my fotopic site some time ago. It is at the end of the blockships collection below. There is also another view by Philip Wilson Steer.
http://shipsintheportofdover.fotopic.net/c1193631.html
There are several other paintings of Dover Harbour in 1918 by Sir John Lavery, who was a war artist, on the Imperial War Museum site which Scotchie has linked to. One of the monitor HMS Terror is of interest. Unfortunately one can only download the thumbnail images.
You can buy a print or an email download, which I intend to do for the Western Entrance painting, but are then forbidden by copyright to display it unless you pay the IWM a fortune. I don't know why museums do this as they are supposed to be the purveyors of information but, in this case, are not doing it themselves and not allowing anybody else to do it for them without charging them an extortionate fee for the privilege.