on the dark and grainy side

I am doing the the AYWMC course as recommended by so many Blippers. I am learning - very slowly. 
This week's homework was to change the ISO - here is photo of P's boots with a high ISO. I believe that this is called "grainy". Hope you can see something there! The thumbnail is barely perceptible! 
I have been a bit wild so have tagged it! Apologies to Cailleach!