Pixelated background

Pixelated background - student project

Pixelated background - image 1 - student projectInteresting class. I love this style of art, and I'm glad to have such an easy way of reproducing it. 

The picture is just something random I found on Google. 

I have one question: what would be a good way of reducing the graininess of the grassy area at the bottom?

Michael Haase
Beginning artist