Adjust upload file options
Here you will learn how to change the available options for uploading files
Step-by-step guide
Login to your administration panel admin.yourwebsiteaddress.com
Go to "Catalog"
Go to "Manage Global Product Options."
Find a global product option and select "Edit."
Here you can change the file types that will be uploaded.
These options extend to everything using that global product option. As such please make sure to select options that match. (i.e: 4/4 should be Front and Back, 4/0 should be Front only.) If multiple file options are chose the customer will be able to upload all of those.