Useful if you're trying to reorganize pictures after migrating out of one photo management service or another that may have resized images or altered the resolution. It doesn't attempt to display the images (that's what feh or imv are for), it only quantifies images' similarity.
I based on the logic on Geeqie's tool for finding similar images. My tool doesn't do anything that Geequie doesn't, except mine is run from the CLI.
At my first job, our lab worked closely with the local TRIGA research reactor, and I did write and run some Java code that analyzed data collected in it. The Java license has always prohibited its use in nuclear reactors, but I figured a little offline analysis would be OK. The results didn't influence the use of radiation in any way.
ImageMagick is old enough and I used it regularly back in the day, but I think (it's been 20 years) most of the data I got was just raw numbers so there probably wouldn't have been much call for it.
I was also working on some (non-nuclear) image processing algorithms at the time, so it's quite likely I ran 'convert' on my laptop while inside the reactor building.
3. RESTRICTIONS ... You acknowledge that Licensed Software is not designed or intended for use in the design, construction, operation or maintenance of any nuclear facility.
Checksumming JPEG files is not that useful (to me, at least). There are lots of cases where the file checksum doesn't match but the image is still the same, for some definition of "same."
Examples:
EXIF/IPTC/etc metadata changes (sometimes this matters; sometimes it doesn't).
Image has been rotated (this almost never matters).
Image saved with different compression parameters (usually this matters but not always).
Image saved with different resolution (ditto).
Image has been slightly edited.
The point here is that with images, data identity does not always equal file identity.
This is the best utility to detect if your image has been transmogrified.