Did actor Keanu Reeves steal a camera from some paparazzi guy and is there a picture of him running away with it circulating on the internet? No, that's not true: the miscaptioned image is actually footage from the set of the movie "Generation Um" in which Reeves' character steals a camera and is chased by people who are trying to get it back.
The picture often appears with following caption:
A photo of Keanu Reeves running away with a camera he took from a Paparazzi guy is currently my favorite photo on the Internet.
This is the image in question:
In reality the image is a set photo from the movie "Generation Um". Other photos from the set can be bought here at this stock photo site:
Download this stock image: KEANU REEVES GENERATION UM... (2012) - DT5HC6 from Alamy's library of millions of high resolution stock photos, illustrations and vectors.
Reeves played the character "John" in the 2012 movie:
Directed by Mark Mann. With Keanu Reeves, Bojana Novakovic, Adelaide Clemens, Daniel Sunjata. Three adults during a single day in New York City, one filled with sex, drugs, and indecision.
This appears to be the scene in question where the character takes the camera, although the viewing angle is different from the picture so it probably was a promotional or media image:
So no, Keanu Reeves is not a camera thief!