Pretty Girls, Ugly Faces is a photo fad in which girls take pictures of themselves while posing in an unflattering manner, making a silly face or performing a physically strenuous activity.

Russia's Ekaterina Birlova casts a shadow on the sand as she serves to Poland during a women's beach volleyball match at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Tuesday, August 9, 2016. (Photo by Marcio Jose Sanchez/AP Photo)

A boy and a serviceman pose for a picture during Marines Day celebration in the Black Sea port of Sevastopol, Crimea, November 27, 2016. (Photo by Pavel Rebrov/Reuters)

A participant in the 5th Lady on Bicycle annual festival opens her bag in the back basket of her tricycle in the Sokolniki park in Moscow on August 6, 2017. The festival's aim is to capture the city's fashionable women on vintage style bicycles. (Photo by Mladen Antonov/AFP Photo)

Princess Diana relaxes on the sand during a visit to the beach on the Caribbean Island of Nevis January 4, 1993. (Photo by Mark Cardwell/Reuters)

A model is styled before the Jasper Conran Spring/Summer 2018 runway show at London Fashion Week in London, Saturday, September 16, 2017. (Photo by Vianney Le Caer/Invision/AP Photo)

People wearing costumes walk during Halloween in Sierra Madre, California, U.S., October 31, 2017. (Photo by Mario Anzuoni/Reuters)

A Palestinian woman takes a picture of a member of the Israeli security forces as he takes her picture in a street in Jerusalem on December 16, 2017, as demonstrations continue to flare in the Middle East and elsewhere over the US president' s declaration of Jerusalem as Israel' s capital. (Photo by Ahmad Gharabli/AFP Photo)