CZIcmd: misleading error message

[ptahmose]

[> I'm also having an issue with CZIcmd:

xxx> CZIcmd.exe -c SingleChannelScalingTileAccessor  -s myfile.czi -r rel(100000,46000,1000,1000) -o tile.png
FATAL ERROR: std::exception caught
 -> Unable to determine the pixeltype.

It's a brightfield image (bgr24) and libczi handles it fine.

I'd think you need to give a plane-coordinate (-p) and a zoom (-z). Please start with "-c PrintInformation -s myfile.czi" and post the result if you are having trouble.

Originally posted by @ptahmose in #8](https://github.com/ZEISS/libczi/issues)

There should be a useful error message in this case, or maybe we can use reasonable defaults.