2.5 x 4 CDV of group of women.  Please us postcard shipping method. 
 
As per Wikipedia --  The carte de vista, abbreviated CdV, was a type of small photograph which was patented in Paris by photographer André Adolphe Eugène Disdéri in 1854, although first used by Louis Dodero.[2][3] Each photograph was the size of a visiting card, and such photograph cards were commonly traded among friends and visitors in the 1860s. Albums for the collection and display of cards became a common fixture in Victorian parlors. The immense popularity of these card photographs led to the publication and collection of photographs of prominent persons.

By the early 1870s, cartes de visite were supplanted by "cabinet cards", which were also usually albumen prints, but larger, mounted on cardboard backs measuring 110 mm (4.5 in) by 170 mm (6.5 in). Cabinet cards remained popular into the early 20th century, when Kodak introduced the Brownie camera and home snapshot photography became a mass phenomenon.