additional info on "spurious low-order bits" warning

[donm]

When loading a 32-bit TIFF, the library warns, "some versions of ImageMagick give spurious low-order bits for 32-bit TIFFs." Can you point me to a thread that discusses this, or provide a little more detail? I'm interested to know exactly what problem I should be watching for, and whether we can detect if the user's installed version of ImageMagick has the problem and/or detect the problem when it actually occurs.

[timholy]

CC @bjarthur

[bjarthur]

perhaps we should uncomment https://github.com/JuliaIO/ImageMagick.jl/blob/master/test/constructed_images.jl#L167-L176 and see if it passes CI with the latest version of ImageMagick. if so, then ] test ImageMagick should reveal whether it works on a particular user's system.

[timholy]

I already tried in #171, didn't pass.