EXIF orientation info in PNGs isn't used for image-orientation
8 comments
·November 21, 2025donatj
MontagFTB
Looping through inflate/deflate on rotated pixels still takes more time than updating a bit in the Exif (and its associated CRC)
LiamPowell
See also: The VLC bug that incorrectly applies right crops as left crops [1]. This bug report is from 2023, however the bug has existed as long as VLC has as far as I know.
I'm always surprised to see bugs like this where an extremely easy to test part of the spec just seemingly isn't tested and ends up as a bug that never gets fixed until many years later.
moron4hire
I firmly believe every product team needs to be split in two: one half works on the issue of highest importance, the other works on the easiest issues. If only to avoid the embarrassment of easy to fix bugs that were passed over for eons just because they weren't priority-high.
silon42
Also, people in the first team should also alternate hard/complicated issues with easy fixes.
mightysashiman
Why does a bug report get shared on hn?
nkrisc
https://news.ycombinator.com/newsguidelines.html
> On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
Someone probably thought it was interesting, and based on the fact it's on the front page and receiving comments, at least some other people agree.
Interesting. I was not aware that was a thing. Orientation info seems way less useful in a lossless format like PNG. It makes sense in JPEG for instance because rotating and re-encoding would be lossy and slightly degrade the image.