The Curiosity Rover's expedition to Mars means a lot of different things for a lot of different people. For NASA, the rover's trip to Mars is the organization's best look at our neighboring planet so far, and is responsible for an immense amount of new data. For average citizens, it's the first step towards the possible colonization of Mars - maybe someday, Earth won't be the only planet we inhabit.
For conspiracy theorists, it's an absolute field day. It seems like new claims of coffins on Mars or UFOs appearing out of no where are revealed and subsequently debunked on a daily basis. No amount of proof will ever deter such wild speculation: if a story is proven false, then it's simply time to move onto the next one.
'The next one,' in this case, is the idea that there's someone on Mars with the Curiosity Rover, performing what appears to be routine maintenance...and this time, there's proof!
What you're looking at there is the a picture of the surface of Mars, with the Curiosity Rover casting a shadow. If that is all you saw, then congratulations: you're in-line with the vast majority of people who have looked at this picture.
Conspiracy theorists, on the other hand, have pointed out that the shadow near the left-hand side of the picture is clearly a technician, working on the rover in some way, shape or form. No, that's not just the rest of the Curiosity's chassis, it's a lone technician that NASA sent along just in case something was up.
The theorists also claim to have access to restricted spreadsheets, and claim that NASA has a group of 'non-terrestrial officers' on standby. Of course, these claims come with stories of unregistered soldiers, top-secrets databases and masterful hacking - so, the typical conspiracy theory schtick. The stories actually go back all the way to 2002: while speaking with Wired.com back in 2006, Gary McKinnon claims that, after hacking into NASA databases, he found evidence of UFOs, extraterrestrials and the non-terrestrial officers.
There are a litany of reasons as to why there's no one on Mars save for the Curiosity: NASA would announce such a huge breakthrough, it's nearly impossible to survive the trip without a massive supply of food on-board, that's clearly just a photo of the rover's hull - but to list them all would be redundant.
If NASA manages to find something on Mars, then it'll be a monumental day for science. Otherwise, it's safe to say that the Curiosity Rover doesn't have a travel buddy.