Have you ever noticed that the bar is much higher for created art over recorded art?
For example, this is a pretty good picture. But a drawing like that wouldn't impress me much, save in its realism.
In my case, and I believe in everyone's case, I expect drawings, paintings, etc to be more than what is physically available. On the other hand, I expect pictures to reveal what actually exists, highlighting the beauty (or horror, or whatever) behind things we might see, things we know exist. Because we perceive photographs as being real, we weight them very differently than drawings or paintings in our mind.
Seeing a corpse in a photo carries a whole lot more emotional meaning than seeing a corpse in a drawing. Of course, the drawing may evoke just as much emotion - or perhaps more - if the artist arranges the picture correctly, establishes an emotional core ahead of time, or uses other tricks of the trade to enhance his drawing over what is "realistic". But the photo, because it is real, inherently has more of a punch.
Now: screen shots.
Which category do they fall into?
It's almost like they take the worst of both worlds, isn't it? They show you what exists... but in a world few care about.