At timew I'm a hack and at times I'm not. I rarely however use premade stuff exclusivly in my images. I most often create the textures I am using, Model my fare share of items. And the lighting and compose the scene myself. If using object that others have created is not art, then Photography is not art, A still life or a sceneic painting in not art. As they mimic or reproduce real live objects. If you must, think of yourself as a virtual photographer. As in real photography you have your subjects and arrange them and frame the photo then take the shot. Photography can and it considered art, so there is nothing wrong with what we do. Only the tools are different. although in my oppinion a person who works with the primitive tools like a brush and paint are the true artists. If we were to use the origional vreation of a image as being the measuring stick, the only abstract or comtemporary are would qualify as they have no resembence to any natural or man made object.