Trouble is there are so many demolished country houses possibly without any pictorial record remaining.
The Death Duties Act 1911 was supposed to do away with them. I don't know the detail but there were relief laws later. Open it to the Public and occupy a small portion of the property, that sort of thing. Then there was English Heritage and the National Trust that tried to preserve as many as possible but I think that was post WWII. Also some bought as hotels or care homes etc.
I remember The Old House at Wexham, Bucks. The old gentleman who owned it died in the mid 1950'sish and it was demolished and modern luxury flats were built on the site. Great pity, probably 17th Century, panelled rooms and a priest hole. The grounds are still recognisable, but that's all. There was a son or grandson with two sons but they couldn't afford to keep it.
Another one was Hedgerley Park, Bucks. Demolished c1938 after death of Mrs Henry Stevenson, RHA. Site was quarried for a short while. It's all overgrown now, but noble trees and exotic bushes evidence it's former glory. There are a few prints of the house extant.