Lock Screen picture on iPhone 13 Pro Max and iPad mini are dark

I don't see any picture. You can customize the lock screen now using iOS 16. You likely need to redo your lock screen. This is not from Apple, but is a pretty good guide on to use the customize features here --> https://www.macrumors.com/guide/ios-16-lock-screen/

You can use your own pictures. Did you read the link and learn how to customize the lock screen, including using your own photo?

Glad to hear it's resolved.