ppmdither
Reduce the number of colors in an image by applying dithering. More information: <https://netpbm.sourceforge.net/doc/ppmdither.html>.
RUN apt-get update && \
apt-get install -y netpbm
RUN apt-get update && \
apt-get install -y netpbm
RUN pacman -S --noconfirm netpbm
RUN apt-get update && \
apt-get install -y netpbm
RUN yum install -y netpbm-progs
RUN dnf install -y netpbm-progs
RUN apt-get update && \
apt-get install -y netpbm