In photoshop go to Image and then adjustments and brightness and contrast. When changing the brightness it can change the mood from sad to happy. Lighter the image the happier the mood and the darker the sadder the mood.
Now I have increased the brightness and contrast of the image and it makes the photo look better by making it warmer. In my opinion this adds more depth to the image by creating more of a ‘glowing’ effect- almost resembling the sun.