A group of allied Prisoners of War. 8 different nationalities on display: Vietnamese, Tunisian, Senegalese, Sudanese, Russian, American, Portugese, and English on the Western Front.
Such images were used as propaganda by the Germans to illustrate to the German people that they were fighting not only a European war but a war of a global nature, whereby the allies employed their colonial troops, and in spite of this, they(central powers) were making gains. A tool used to pump up morale amongst the Germans and central powers.
Original image source: National Archive/Official German Photograph of WWI