Scan a page from a photo in the iOS Notes app

The Notes app has a nice feature to "scan" a letter by clicking the camera icon and selecting "scan document". This will use the camera, search for a letter-like object, correct tilt and optimize the picture and insert the result into the note. Sometimes I have a picture of a piece of paper that I would like to transform in the same way. Unfortunately, it seems the Notes app only allows the camera as input to "scan document" and not a picture. Is there a workaround to achieve the same result when the input is a picture?