Comment on Image upload error?

InEnduringGrowStrong@sh.itjust.works ⁨1⁩ ⁨month⁩ ago

• threelonmusketeers@sh.itjust.works ⁨1⁩ ⁨month⁩ ago

  Thanks for the info! The file extension is png.

  source

  • InEnduringGrowStrong@sh.itjust.works ⁨1⁩ ⁨month⁩ ago

    Would you mind sending me that file through another means so I can test what’s happening?
    Whatever file host, matrix, email, etc.

    Thanks

    source

    • threelonmusketeers@sh.itjust.works ⁨1⁩ ⁨month⁩ ago

      Thanks! I just sent it on matrix.

      source

      • InEnduringGrowStrong@sh.itjust.works ⁨1⁩ ⁨month⁩ ago

        Got it.

        Your PNG contains extra data after the PNG’s IEND marker which pict-rs probably errors on.
        Your images aren’t stored as-is, among other things, their metadata is stripped so people don’t unwittingly share their geolocation, etc.
        It rewrites the file in the process, but in this case doesn’t know what to do with the non png compliant data appended at the end.

        Here’s a fixed version of your image that uploads fine.

        Image

        Using pngcheck -vf on the original image will give you the starting hex offset (0x10fc31) of that invalid chunk of data, which can then be browsed with whatever hex editor.
        I haven’t investigated that extra data much.
        It might be part of a ‘capture the flag’ game, or not.

        The fixed image is just the first bytes of the file upto that invalid extra chunk.

        source

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