1900s - John Fraser - and Edoardo De Martino
Fraser was an English marine artist who collaborated extensively with Commendatore Eduardo de Martino, Marine Painter-in-Ordinary to Queen Victoria. Martino also enjoyed special favour with Edward VII, who never went to sea without him. When the Italian died, Fraser thought he would succeed him. He didn't - perhaps the King possibly found him too boring!
I cannot find any record of him having visited Gibraltar but his representations of the Rock are impressive. Here are three of his pictures.
Three Quarter Merchantman and Xebeck
Edoardo Federico de MartinoDe Martino was an officer in the Italian Navy, but turned to painting when he was thirty. He became very well-known in London because of his paintings of famous British naval victories.
Two warships in a swell in the Straits of Gibraltar
The warships have possibly been identified as HMS Diana and HMS Andromeda escorts to HMS Ophir on the Dominions Tour of the Duke and Duchess of Cambridge and York in 1901 ( see LINK )
The Arrival of the Victoria and Albert
The Departure of the Victoria and Albert