SignedShortLosslessBug.jpg

[omniplex]

In the SourceForge JPEG project (a source code collection of various JPEG libraries) somebody published a test file SignedShortLosslessBug.jpg. Sadly XnView can't handle this, the Windows photo viewer also hates it.

FFmpeg 2.1.3 accepts the test picture and can convert it into a PNG. FFprobe 2.1.3 claims that this image uses pix_fmt=gray16le, and XnView confirms this theory for the PNG, i.e., I get the usual "too many bits per color reduced to 8 bits" warning when I look at the gray PNG. Eventually I tested the 64bit version of nconvert -fullinfo, and got Error: Contact your dealer. Done

[xnview]

yes lossless jpeg not supported

[omniplex]

yes lossless jpeg not supported

MediaWiki also hates this beast (not sure what they really use, presumably GIMP or Magick), I parked both versions in the Commons JPEG artefacts category.