Seconding the recommendation of CLIP embeddings, especially compared to image histograms + requiring OpenCV. I wrote a naive, minimal dependency Python package

Seconding the recommendation of CLIP embeddings, especially compared to image histograms + requiring OpenCV. I wrote a naive, minimal dependency Python package to calculate image embeddings (https://github.com/minimaxir/imgbeddings https://github.com/minimaxir/imgbeddings) with some lookup demo notebooks and it works well in a pinch, although it's due for an upgrade.