The National Gallery's incoming director, Mr Powell, has several key curatorial posts to fill.
The society has also established a new curatorial post: associate curator of contemporary Asian and Asian-American art.
Both exhibitions are curated by the Centre's director, Paolo Colombo, who previously held curatorial posts at North Illinois University Art Gallery and at Philadelphia's Tyler School of Art.
Even so, he eliminated 10 of 105 curatorial posts and fused some departments.
He combined this curatorial post with a professorship at New York University's Institute of Fine Arts, and enjoyed mixing with the city's high society.
To succeed Mr. Varnedoe, Mr. Lowry appointed John Elderfield, who has held several important curatorial posts at the museum, since 1993 that of curator at large.
After art school he worked in the Metropolitan Museum's education department, traveled to Africa, and in the early 1980's accepted a curatorial post at Longwood Art Center in the Bronx.
He held the honorary curatorial post from 1892 until he became secretary of the Smithsonian in 1907.
Mr Walsh has led the Getty Museum since 1983, before which time he held curatorial posts at the Museum of Fine Arts, Boston, and at the Metropolitan in New York.
Mr. Elderfield succeeds Kirk Varnedoe, who organized "Matisse Picasso" with him, in what is generally recognized as the most significant curatorial post in modern art.