Hi, @vtncanada.

I appreciate you performing the steps to create the cheque electronic signature. I can help get this working for you.

This function should be available using the QuickBooks Premier Nonprofit. Once you click the Print Signature Image checkbox, the Signature dialog box will open. You can then proceed in clicking the File tab that will let you select the graphic file that contains the signature.

Since this option is missing, I'd suggest updating your QuickBooks to improve program functionality and fix known issues. 

Please let me know if you're able to see this option after the update. 

Should you need other troubleshooting steps that'll be helpful in the future, you may refer to the following articles below.

Fix QuickBooks Desktop Update Errors

Unrecoverable error in QuickBooks Desktop

I'll be on the lookout for your reply if you need further help with this. Have a good one.