Ah! In this case, you might be happy to discover that ExifTool just added an "image content" hash--it's the SHA (or MD5 or whatever) hash of the _actual image bytes_, after ignoring the metadata header (and possible footer) payloads.
So if you, say, change the rotation of your RAW image file (which normally will just add or change the EXIF `Orientation` tag), the image content hash will stay the same.
His tool is in rust, so he can directly call the libraw function. ExifTool is a perl tool, so it'd be an external process that he'd need to coordinate with.
So if you, say, change the rotation of your RAW image file (which normally will just add or change the EXIF `Orientation` tag), the image content hash will stay the same.
See https://exiftool.org/ExifTool.html#ImageHashType
(of course, your current approach should prove substantively faster, but will only work with the formats that libraw supports)