When scanning an invoice or when importing an invoice via the share dialog in mail, you get this nice screen where you can check if everything is ok. But it's not possible to see the original file. When you take a photo of an invoice I get this, because you have the thing in your hand. But when you import from mail, you have to switch apps multiple times to check it.
Really would like to see the source or at least have a link to the source here.