No idea mate, dunno where it came from, it might have even been my Nan's picture, I'm not sure. I've got some other pics of Highfield Road kicking about, I'll try and post them.
The Spion Kop Terrace was built in 1922. It was made all seated in 1981 when Coventry City became the first club in England to have an all seated stadium. The experiment failed four years later the seats were removed from the Kop (East Terrace) and it became all standing once again. The Kop was replaced by a new stand (costing �4.3m) in 1993.