I have recently started trying to get my head around Photoshop, I know, I'm a dinosaur. I am a bit of a purist and always thought that the image had to be perfect 'in camera'. While I still work hard to get exposure and composition correct while out shooting I do find it intriguing to see how differently a photo can look by simply changing a background.
Photography is an art form - photos can seek to accurately represent exactly what the eye sees. This is what I aim for with bird photography.
Other photographs change the way that we see an object, This is often a technique I use when taking long-exposures in changing light (example below).
Is there a right or a wrong in photography? I don't think so. Some of the images I take and subjects I choose will have no appeal to some people, others will love them. It really doesn't matter as long as I make someone stop and think about what I have taken. Powerful stuff this art business.