This is excellent!

In the past, I used Grafx2 (https://pulkomandy.tk/projects/GrafX2) for 'beadifying' an image. It can reduce color palettes to powers of 2 (2, 4, 8, ...), then provides a count of each color in the image. This way, I knew precisely how many beads I'd need (useful when certain colors were in limited supply, and as a checksum).

I'd match these colors as closely as possible to my beads, count them out, and start laying - using the on-screen image as a guide.

Your tool is better, of course ;-)