Sand dunes in Southern California. Original image from Carol M. Highsmith’s America, Library of Congress collection.… Free Image from public domain license 
The Starry Night (1889) by Vincent Van Gogh. Original from Wikimedia Commons. Digitally enhanced by rawpixel. Free Image from public domain license 
The Repast of the Lion (1907) by Henri Rousseau. Original from The MET Museum. Digitally enhanced by rawpixel. Free Image from public domain license 
Giraffe (Giraffa camelopardalis) illustration wall art print and poster. Free Image from public domain license 
Indian peafowl (Pavo Cristatus) illustrated by Charles Dessalines D' Orbigny (1806-1876). Digitally enhanced from our own… Free Image from public domain license 
Le Ballon by Imprimeur E. Pichot. Original from Library of Congress. Digitally enhanced by rawpixel. Free Image from public domain license 
Chinese pattern from L'ornement Polychrome (1888) by Albert Racinet (1825–1893). Digitally enhanced from our own… Free Image from public domain license 