Image from Wikimedia Commons
original uploader - CC BY-SA 3.0
Morelli Gusztáv - Public Domain
original uploader - Public Domain
US Government Printing Office - Public Domain
Bonar, Andrew A. - Public Domain
kris krüg - CC BY-SA 2.0
A. Legrand - Public Domain
Ingmark - Public Domain
George Albert Smith - Public Domain
Unknown - Public Domain
Public Domain
unknown - Public Domain
Unknown, possibly a self portrait - Public Domain
U. S. Army Signal Corps. - Public Domain
*:File:3rd_Duke_of_Northumberland.jpg - Public Domain
Sjakkelien Vollebregt / Anefo - CC BY-SA 3.0
Image from Wikimedia Commons
Oliphant, Laurence, 1829-1888
Image from Wikimedia Commons
Hölderlin, Friedrich, 1770-1843
Image from Wikimedia Commons
Keller, Marthe
Image from Wikimedia Commons
original uploader - CC BY-SA 3.0
Egorov, Youri
Image from Wikimedia Commons
Henry-Haye, Gaston
Image from Wikimedia Commons
Morelli Gusztáv - Public Domain
Kisfaludy, Károly, 1788-1830
Image from Wikimedia Commons
original uploader - Public Domain
Cuyler, Thomas Dewitt, 1854-1922
Image from Wikimedia Commons
US Government Printing Office - Public Domain
Valeo, Francis R. (Francis Ralph), 1916-2006
Image from Wikimedia Commons
Bonar, Andrew A. - Public Domain
M'Cheyne, Robert Murray, 1813-1843
Image from Wikimedia Commons
Goodrich, Arthur Frederick, 1878-1941
Image from Wikimedia Commons
Leys, Hendrik, Baron, 1815-1869
Image from Wikimedia Commons
Zafzāf, Muḥammad
Image from Wikimedia Commons
kris krüg - CC BY-SA 2.0
Navarro, Joe, 1953-
Image from Wikimedia Commons
A. Legrand - Public Domain
Devergie, Alph. (Alphonse), 1798-1879
Image from Wikimedia Commons
Ingersoll, Joseph R. (Joseph Reed), 1786-1868
Image from Wikimedia Commons
Ingmark - Public Domain
Coventry, Keith, 1958-....
Image from Wikimedia Commons
Hogg, James Stephen, 1851-1906
Image from Wikimedia Commons
George Albert Smith - Public Domain
Smith, George Albert, 1870-1951
Image from Wikimedia Commons
Cassavetes, John, 1929-1989
Image from Wikimedia Commons
Unknown - Public Domain
Erlanger, Abraham L., 1859-1930
Image from Wikimedia Commons
Public Domain
Perrot, Jules, 1810-1892
Image from Wikimedia Commons
unknown - Public Domain
Díaz Soto y Gama, Antonio
Image from Wikimedia Commons
unknown - Public Domain
Larkin, Milt, 1910-1996
Image from Wikimedia Commons
Unknown, possibly a self portrait - Public Domain
Watson, Edith S., 1861-1943
Image from Wikimedia Commons
unknown - Public Domain
Cambridge, Ada, 1844-1926
Image from Wikimedia Commons
Kellermann, François-Christophe, duc de Valmy, 1735-1820
Image from Wikimedia Commons
Hobart-Hampden, Augustus Charles, 1822-1886
Image from Wikimedia Commons
U. S. Army Signal Corps. - Public Domain
Palmer, John McAuley, 1870-1955
Image from Wikimedia Commons
*:File:3rd_Duke_of_Northumberland.jpg - Public Domain
Northumberland, Hugh Percy, Duke of, 1785-1847
Image from Wikimedia Commons
Sjakkelien Vollebregt / Anefo - CC BY-SA 3.0
Brown, Christopher, 1948-....