After receiving and responding to a commercial request this week I thought I would share/remind everyone of some info about stock. :)
Just because stock is uploaded on DA doesn't mean you can use it for every project.
Some places, and even objects, are controlled by third parties or copyrighted. Even if the stock artist took the image they may not have permission to use the likeness in the image.
Example: An image taken of the Eiffel tower at night is copyrighted. Meaning that you can take a picture of it, but you cannot use it in any type of commercial endeavor (including prints).
From SETE website "The various illuminations of the Eiffe