Montevideo, Aug 13 (Prensa Latina) The image of Fidel Castro appeared everywhere in Uruguay this morning, as hands in solidarity displayed banners and posters, or drew his likeness as a revolutionary fighter.   The banners and signs bear acronyms—PCU, UJC, FA—referring to the Communist Party of Uruguay, its Communist Youth wing, and the Broad Front (Frente Amplio); they are appearing across Montevideo, departmental capitals, and various other localities.