The hue of an image refers to the color (red, orange, blue ...). When an image has a predominant color it has that hue.
Brightness refers to the amount of light received. The percentage of brightness that appears in the bottom part is relative to the minimum and maximum brightness that can give the monitor of your computer. But the brightness 0% and the brightness 100% would be absolute luminosities much more intense than the ones that you could observe on the screen.
Saturation refers to the vividness or color paleness. The image has minimal saturation when the three components of white light arrive with the same intensity in each of the tones of the image (black and white image is seen) and high saturation when there is a dominant wavelength that causes We perceive strongly in each area of the image a single color.
