*Actually, Trotsky wore his beard and glasses continuously since 1915, and low-res photos do not contradict this (see the Wikimedia Commons version!)  There is a rather more detailed and hence credible interpretation of this poster from a quite reliable source here: 
 **Tate Modern publication Red Star Over Russia (pg. 98), on the "Russian Revolutionary Posters" collection: 
 : 
 :The evidence is rather against this being Trotsky.