How did Edward Steichen contribute to the Photo-Secession?

Edward Steichen was a foundational member of the Photo-Secession, a group established in 1902 by Alfred Stieglitz to promote photography as a fine art. His contributions were instrumental to the group’s influence and reach:12

• Gallery Leadership: Steichen helped Stieglitz open the Little Galleries of the Photo-Secession, known as "291." He served as the gallery's "French connection," leveraging his European contacts to organize groundbreaking American exhibitions of French Modernist art, including works by Auguste Rodin, Henri Matisse, and Paul Cézanne.32
• Publication: He was a primary contributor to the group's influential journal, Camera Work. Over the magazine's 14-year run, it featured more of Steichen’s photographs—68 in total—than those of any other photographer.2
• Artistic Advocacy: As a talented practitioner of Pictorialism, Steichen used his background in painting to create manipulated, atmospheric prints that helped persuade the public to view photography as a legitimate fine art form.2