As far as I can tell, there isn't an easy way to convert a color image to grayscale in Pro.
There appears to be a raster function for converting an image to grayscale, but it doesn't seem to do what I want, at least not as easily as I would like. Convert color image to grayscale
It would be great to have a simple geoprocessing for converting a color image to grayscale, for the purpose of classifying the image: Easily remove white pixels from georeferenced plan.
Raster Symbology — Automatically convert color raster to grayscale to support Classify primary symbo...
