I think it depends. If the subject matter appears to be of a particular company (lets say you got a coca cola truck where the entire image is the red coca cola truck with the logo very visible), then yes, I think you would have an issue. (It would seem like you were selling 'coca-cola' t-shirts). And if coca cola saw that, and happened to defend their trademark, then yes, you'd have an issue.
If, however you say have a landscape picture, and a coca-cola truck happens to be in the picture, albeit very small (i.e., maybe 1/20th of the image), and you have a whole bunch of other buildings, then that is an entire different thing, because the subject matter is of a 'landscape' photo.