Hi!
Active card checks are where a website checks the security details of your card, in addition to making sure it’s a valid, working card in the first place.
The photo part is the same receipt saving feature you’ll find on every other transaction, you can ignore it as there’s no receipt to save here.
As for the decline itself, could you make sure the billing address you’re entering in eBay/PayPal is the same as shown in the app and let us know using the in-app support chat? If it’s what I think it is, it’s an easy fix. 