The photo was not photoshopped. I can see why some people would think it was though because of the sharp definition between the Babe and the background. However, that sharp definition is easy to do by someone who is a very good photographer and when it's printed properly by hand and not by a machine. I'm pretty sure they didn't have automated photo processors back when that was shot. The fine detail was probably also the result of using larger format, slow speed black and white film. Back then the standard news camera was used 4x5 inch sheet film. The larger the film size, the more refined the detail will be when the image is properly shot, processed and printed.
You can get the same basic result with a digital camera but you would have to "photoshop" the image to do so.