Even without a GPU, the JPEG format itself allows for totally lossless rotation.... | Hacker News

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		ryandrake 40 days ago \| parent \| context \| favorite \| on: EXIF orientation info in PNGs isn't used for image... Even without a GPU, the JPEG format itself allows for totally lossless rotation. It is also quite fast, and doesn't require reading and writing every pixel in the image.

thunderfork 40 days ago [–]

Isn't this only true for images where the resolution is divisible by the block size or something like that?

IIRC in other cases you have to cut the edge of the image off (rounded to the nearest block) or recompress those edge blocks

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