Painters have enhanced their subject matter for centuries. However with paintings we commonly perceive them to have a subjective quality, were we expect artistic freedom. We haven't expected this same degree of freedom from photographers.
Certainly pictures aren't the only thing who's reality is suspect. I've long questioned the authenticity of many/most television shows and movies. "Reality television" is about as fake as fake can be. At least with movies coming from Hollywood, we knew what to expect; most often glamorized fiction of some sort.