2, "photo slimming" has an impact on clarity, which will make the photo slightly blurred. This change in clarity is almost imperceptible to the naked eye, but "photo slimming" can greatly reduce the size of the picture.
3. "Slimming" photos cannot be restored, and image compression ("Slimming" photos) is an irreversible process.
Extended data:
The reason why photos can be compressed is because the data of photos are redundant.
Image compression mainly includes spatial redundancy caused by the correlation between adjacent pixels in an image, temporal redundancy caused by the correlation between different frames in an image sequence, and spectral redundancy caused by the correlation between different color planes or spectral bands.
Image compression can reduce the number of bits needed to represent data by eliminating these data redundancies.