This photos contains the primary elements of ISO called “Lighting and Grains”. 
    ISO is a setting or a tool in a camera where you can navigate the light inside your camera. This helps the photographer to enlighten the image even if it is dark temperature but the side effect of it, is the higher the ISO the more the grains that will appear in the image. It is one of the fundamental skill of the Photography , It serves us the artificial light of the photography. 

I hope this helps you in your Photography. 
Have a Nice Day. :)