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A comment on PNG Is Back. Parent comment

Re:PNG Is Back by liuliu on Wednesday June 25, 2025 @12:28PM (#44379111)
JPEG XL has the mode that in layman's word, allow bit-by-bit round-trip with JPEG.

Original JPEG -> JPEG XL -> Recreated JPEG.

Sha256(Original JPEG) == Sha256(Recreated JPEG).

That's what people meant by "backward compatible".

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Re:PNG Is Back by colejohnson66 on Wednesday June 25, 2025 @12:56PM (#44379451)
That’s not “backwards compatible”, but “round tripable” or “lossless reencode”
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Re:PNG Is Back by illiac786 on Monday June 30, 2025 @05:43AM (#44421291)
exactly, it is absolutely not backward compatible. It is lossless-at-bit-level conversion of JPEG, but that doesn’t help older SW in any way.
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