The image, said to have been taken by the NASA rover on April 21, has been uploaded to website ufosightingsdaily.com
The rover is on Mars exploring the Red Planet for NASA before beaming back the images to earth which are placed online by the US space agency.
Several UFO hunters then pour through them looking for signs of alien life.
Scott C Waring, editor of ufosightingsdaily,com said: “I found this footprint on Mars that looks like a human shoe print.
“The footprint was in a Mars rover photo and might not be a recent print, but may actually be the foot print of a bipedal species that walked this planet long ago.
“The foot print could be a petrified footprint, much like the dinosaur foot prints found here on Earth.”
Mr Waring is convinced that Mars either was, or still is, inhabited by a race of intelligent beings after spending hours looking through the images.
NASA denies the rover has found any evidence of even the most basic forms of life.
It says this, and earlier, so-called discoveries, are just the effects of pareidolia.
This is when the brain tricks the eyes into seeing an object or shape that we recognise in patterns or textures like a rocky surface.
In short, couple with an active imagination, people see what they want to see.
It is not the first time that alien chasers have claimed to see footprints on the surface of Mars.
A number of rover images were highlighted that appeared to show complete trainer prints, complete with the tread.
However, it later turned out they had been made by the tracks of the rover itself.