A contact sheet can both be used for distinguishing between your good/bad photos and choosing which ones to use/ edit, or be used as a finished photo. This is because of the image selecting process being used.

Here I have used green to mark photos which I am going to use, red to mark photos which I am going to discard, purple for the area of a photo I will crop, and yellow for pictures which I am unsure about using.

For future projects I will crop and edit the images which I have chosen from the contact sheet, and potentially crop the contact sheet to show only a few photos, which I will annotate with a thick marker and use as a finished photo.