Back in 2007 two researchers came across a photograph often exhibited as proof of African Americans in Confederate service–a image labeled “1st Louisiana Native Guard.” An examination of the photograph revealed that the image in fact was of African Americans in Union service: one way in which the image was tampered with in order to misrepresent it was by cropping out the Union officer.
News of this find has been around for years. Blogs pick it up all the time. Last month Jubilo featured it; that blog’s author had also pointed to it in another blog in 2009 (you might want to read the comments). It’s been a subject addressed in lectures.