Takes a colormap argument, an image and transforms it by going to greyscale and then to the colormap.
You need imagemagick installed, follow instructions from here
go install github.com/f01c33/colormap@latest
colormap magma nature.webp
colormap inferno nature.webp
colormap viridis nature.webp
colormap cividis nature.webp
colormap twilight nature.webp
colormap turbo nature.webp