Grid and Grayscale Image Tool
This tool will apply a grid and grayscale to your reference photo (without needing to use any tedious software).
Step 1: Upload your reference photo below ("Choose File").
Step 2: Wait a moment while your photo is processed.
You will get three versions of your reference photo: one grid; one grayscale; one with both. If you need reference photos, you can get access to mine here.
(NOTE: We understand some people are having issues with this on mobile. We are investigating and should have the tool fixed shortly for mobile. Desktop works fine.)