Rock, Paper and Scissors images are from https://www.iconfinder.com/
(they are still striped, as printed on the website, since I didn't pay for them)

Spock image was found here http://all-free-download.com/free-vector/download/spock-star-trek-cartoon_52494.html

Lizard image was found here http://www.symbols-n-emoticons.com/2014/07/likable-lizard.html

favicon from here https://fr.findicons.com/icon/441883/applications_games

GIF source: https://www.pinterest.com/pin/587930926353765433/
(edited with https://ezgif.com/)

Question mark: https://fr.m.wikipedia.org/wiki/Fichier:Question_mark_alternate.svg