This image is taken from the Public Health Image Library (PHIL), a division of the CDC. The description of the image specifically states that it is in the public domain: "This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image." It is credited to Christina Wozniak at the Houston Zoo. I downloaded the high-resolution TIFF from the website and re-saved it in the PNG format (compression level 9) using GIMP. This reduced the file size by about half while resulting in no loss of visual information. Original URL: [1]. Due to the extensive use of server-side scripting on the PHIL website, it is impossible to link directly to the image description page, but it can easily be located by going to this search page and entering the image ID (8134) in the search box.

Esta imagen es una obra de los Centros para el Control y la Prevención de Enfermedades, parte de los Departamento de Salud y Servicios Humanos de los Estados Unidos, adoptadas o realizados durante el desempeño de funciones oficiales de un empleado. Como una obra de los Estados Unidos del gobierno federal, la imagen es de dominio público.