Combine the first channel of four separate image files into one, four channel image.

[mprater]

ImageMagick version

6.9.13-14 Q16 x86_64 18442

Operating system, version and so on

Rocky 9

Description

The title says it all. I have four separate image files. Each contains a different gray-scale image. I need to combine the first channel from each of these into a single output image that contains the separate content of each input file as a channel value in the result.

Thanks, mitch