These are words about a photograph, not the photograph itself.
So you're making a distinction between the physical photograph and the photographic content.
But on this distinction, a photograph is not "about form, shading, color, perceived texture, balance and harmony of the related parts": it's just metallic silver atoms (or digital bits, or pigment on a paper).
In the same way, spoken language is not "about thoughs, feelings, comunication": it's just soundwaves in a certain frequency range.