Prevent attachments to invoices during email approval

Summary:

We would like to prevent users from being able to add attachments to an invoice record during the payables invoice approval process when approving via their personal email address. We are facing issues in which email signatures are being attached as .png images to the invoice records, and we are unable to turn off the signatures in a way that will not send these as attachments when a user approves an invoice from their email.

Is this possible via a setting?

Thanks,

Brent