How do I put a grid graph(Coordinate plane) over an image?

For my algebra 2 class I must take a picture and find its quadratic equation(parabola). I chose the St Louis arch. In order to do this I must place a graph over the picture and print it out. How do I do it?How do I put a grid graph(Coordinate plane) over an image?
Find a photo. Draw a line every inch or centimeter. Also put your 'zero' line (y axis) on the center of the arch and the feet of the arch on the other zero (the x axis). You might wanna scale your squares to fit evenly into the height of the arch. So make sure theres like ten squares between to top and the base. This will make calculations easier.



Remember you can scale your graph however you want. Use this to your advantage.How do I put a grid graph(Coordinate plane) over an image?
I'm doing the same project! I simply printed the picture out on graph paper :)