We started with #LosslessCompression. Across a range of general-purpose (GP) compressors, we found that #Zstandard with
@Blosc2 achieves the best compromise between compression ratio and decompression speed!

NP1: compressed size ~36%
NP2: compressed size ~52%

(3/n)

So, if nothing else, if you are #publishing a book or #archiving your own media with phone images, start from a #LosslessCompression image format and try to keep them saved in that or another lossless format instead of JPEG.