2) Instantiate the image in the new project. This requires you to have access to both projects.
You can see the URL of your image in the Images tab under “Equivalent REST” in the console.
In Google Developer Console, select the old project and go to Compute -> Compute Engine -> Images. Click on the new image (i.e. ), select Equivalent REST and copy the link (something like https://www.googleapis.com/compute/v1/projects//global/images/)