First time I write about SplitRaster+ by Roudoudou even if it was first out in 2019... It's a line command utility for windows, linux and macos which converts PNG pictures for Amstrad CPC+ up to 1000 couleurs ! Yes you did read this number, but seriously usually it will be around 300-500 colors, by using rasters and Amstrad CPC+ hardware sprites.

You can download SplitRaster+ 2025 on Github. I let you check what it can do (extracted from CPCWiki) :