eh, maybe something on ur sensor?
try taking some photos against a bright background and look at the same spot.
if it's there, try cleaning the sensor. i usually use a blower to get dust off my sensor.
hope this helps.
Just some loose speck that has landed on your sensor surface. Nothing a little blowing with a rubber air puffer can't relocate it...hopefully away to some other part of the camera chamber or out of it altogether. Lock your camera mirror up so you have access with no obstruction leading to the image sensor. Break open your camera by removing your lens. position the lens coupling opening towards the ground and use your rubber air puffer to blow about the interior of the camera. Put your lens back on and shot off a shot at a white wall or background or a white out sky and then load it on your PC and zoom in to see if you can still see it there or not. If it is still there but have move to another part of the image...well...repeat all the above until you don't see it anymore...tile the next time it pops out again.