Because our human nature recognizes the primary and secondary characteristics of color and form, making them intelligible for the emotions  and reasoning. And even from the sensations and perceptions of our senses.  Since, there is an answer from the touch of our skin towards the color and specially,  when we are in front of an image because this, naturally evokes and internally identifies with its correlated feeling. The perception is given because every image evokes an ideational line of feeling and thinking and from there, we recognize and differentiate between harmony and lack of harmony, between happiness and sadness, between a source of creativity or a source of destruction ...continued>