Hobbyist and professional costumers, dedicated to the promotion and education of costuming & cosplay. The International Costumers' Guild, Inc., is an affiliation of amateur, hobbyist, and professional costumers dedicated to the promotion and education of costuming as an art form in all its aspects.The International Costumers Guild (ICG) is dedicated to the promotion and education of costuming as an art form in all its aspects. It also advocates on behalf of its members and the costuming community in matters of public interest related to the art and practice of costuming. The ICG was formed in 1985 to bring hobbyist and professional costumers from around the world together, and to foster local educational and social costume events.