What happened to the blades in this picture? Here is the picture  


Source:(brians-travels.com)  

This looks like a photoshopped picture, but I believe it isn't. Is this some kind of strange occurrence that occurs only with the human eye? The blade on the top looks bent downwards. I can't figure out what happened in this picture. And will your picture look like this every time you take a picture of a fast moving propeller?
It's an artifact of how a digital camera downloads captures the image from the sensor called rolling shutter.

Essentially the image is captured a single line at a time and the fast moving propeller changes location between each line captured.

Wikipedia has a nice diagram showing what happens step by step:



On our sister site photography.SE has a question asking about it.