Can you further explain that cash deposit to credit card payment process through an ATM? I've only ever used ATMs to withdraw funds, never to make deposits, so I don't know what that process would look like or which banks would let me do that.
1: https://www.bankofamerica.com/banking-information/assistance...
How are you paying cash online at all?
Then I had an idea - I got a piece of black construction paper for a background and it was much happier taking pictures of checks on that.