[cenamus]

Perceptual hashes are very good for that, maybe with some adjustments for mirrored images and some crops

[punnerud]

Can use dhash that is more robusts to compression, crops and color changes. Mainly look at the features in the image.

[mkl]

The README explicitly says it's not good for crops, and from the algorithm description it can't be. Or is there another thing called dhash with a different algorithm? https://github.com/benhoyt/dhash. https://github.com/Rayraegah/dhash is similar but horizontal only.

[ggm]

Yes. Most of the systems I used a couple of years ago (immich for instance) were still quite immature.