On Quest, taking rotated (portrait) picture will generate broken png file.
I've tested all 4 directions with 720p/1080p with/without timer, in total 16 patterns, only 4 patterns with right side up will generate valid png.
Broken png may be all pixel are black but may have some noise.
The 1st picture is right side up (horizontal) picture and it's valid PNG.
The 2nd is vertical picture and the 3rd is upside down and they're broken.
ADDITIONAL INFORMATION
My friend says with PC version of VRChat, this is not happens.

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