Product Builder requires a lot of images created at specific sizes. Here's a great free web app that you can use if you're not comfortable with Photoshop:
As of February 19th, 2021, Product Builder is unavailable for new installations. If you are currently using Product Builder, you will be able to continue using the app as your account will now be grandfathered.
Do you need 360 Images? We highly recommend Jamie with Visual Integrity at Visual Integrity Studios. He has very reasonable prices and a fast turn around time.