These images are discussed at Franck Benoiton's 'From to Anton to Karl' Bf 109 FB page. Even the 'experts' are confused by the various Schlacht unit designations. In Prien JFV 4/II the Mickey Mouse emblem appears on 4.(S)/LG 2 machines and this is Sch.G1 from April 1942. Note the infantry support emblem under the cockpit of 'Red' or 'Black L'.
A photo feature on Schlachtgeschwader 1 appears in Erik Mombeeck's Luftwaffe Gallery 1
More Emil Jabos in the East on this blog here