Excellant Points;
Matthew Brady and other were not taking photographs for historical documentation. They were taking those photos to sell and for profit. There are reports of Brady and others destroying hundreds of glass plate because they did not sell. What a waste of history. We also know that they staged the dead bodies for dramatic effect also such as the famous photograph of the dead Confederate Sniper at Devil Den Gettysburg.
So what does that say about the Photograph of "Gordon's" whipping and the seeming absence of other such photographs? Is it a reliable photograph? While I am sure the marks on his back are legitimate, the question remains were they caused for the reasons that we are asked to believe? Since it was most likely a Photograph that was purchased, we have to ask was it "staged" for political purposes?