There is a method in Photoshop where you can re-create images in a low-rendered polygon form. The way we were taught this was we used a picture of a Robin (below)
In order to achieve this and to speed up the process, we created an F1 shortcut called poly-fill. I did this by recording a set of actions on the action tab brought up in the windows menu and setting the action to the F1 button by enabling those commands in preferences, keyboard.
Afterwards (using the polygonal lasso tool) I began outlining triangles on my Robin and pressing my new F1 command to fill it with a polygonal colour, while making sure that the triangles fit together by starting the outline from one point of the previous triangle to the next.
When i had completed the polygon-ing of my bird, to complete the picture i added a grading green background to make it look more refined. When i had finished, my Robin looked like this: