Complex sentence: Nijinsky is immortalized in numerous still photographs, many of them by E.O. Hoppé, who photographed the Ballets Russes seasons in London extensively between 1909 and 1921.
Split into simpler sentences: Nijinsky is immortalized in numerous still photographs, many of which were made by E.O. Hoppé. He photographed the Ballets Russes seasons in London extensively between 1909 and 1921.