241543903 (a.k.a “Heads in Freezers”) is a numerical keyword associated with a photo meme that involves people taking pictures with their heads in the freezer & sharing them online. By tagging a series of image files with a cryptic number, a high level of search engine optimization can be easily achieved. As a result, typing “241543903” into image search engines like Google Images successfully yields pages after pages of pictures showing people’s heads in freezers.
In 2009, David Horvitz started the “Heads in Freezers” meme. Participants took photos of their heads in freezers, tagged them with “241543903” and uploaded them to social media sites like Tumblr.

People take part in the Cupid's Undie Run in the Manhattan borough of New York February 7, 2015. The run, held to raise funds to combat children's tumors, sees runners in their underwear partying and running along the West Side Highway. (Photo by Carlo Allegri/Reuters)

Vegetarian 19-year-old model Courtney Stodden gets ready to serve veggie hot dogs wearing a lettuce bikini during a People for the Ethical Treatment of Animals (PETA) free veggie dog handout on Capitol Hill in Washington, DC, July 16, 2014. (Photo by Jim Watson/AFP Photo)

This picture taken on July 25, 2014 shows people cooling off in a waterpark in Suining, southwest China's Sichuan province. Meteorological departments issued an orange alert for high temperature as a heat wave embraces Sichuan province, with temperature of most area topped 37, local media reported. (Photo by AFP Photo)

Bangladeshi people walk in a polluted air environment in Dhaka, Bangladesh on September 3, 2020. A study says, air pollution shortens life expectancy by seven years in Bangladesh. (Photo by Sultan Mahmud Mukut/SOPA Images/Rex Features/Shutterstock)

People wear face masks as they ride an E-scooter in the Old Elbe Tunnel in Hamburg, Germany, Thursday, October 15, 2020. To avoid the spread of the coronavirus the use of a face mask in the 117-year-old tunnel under the Elbe river is mandatory. (Photo by Michael Probst/AP Photo)

People socialising in Soho, central London on July 11, 2020, after the lifting of further coronavirus lockdown restrictions in England. Revellers are urged to remember the importance of social distancing as pubs gear up for the second weekend of trade since the lifting of lockdown measures. (Photo by Stefan Rousseau/PA Images via Getty Images)

People take part in the Million Mask March anti-establishment protest at Trafalgar Square in London on November 5, 2020, on the first day of a four week national lockdown for England. (Photo by Aaron Chown/PA Images via Getty Images)