When I create a map, which uses 13 different colors (12 + gray for background), why uses(!!) QGIS more than 20000 different colors when saved as bmp, png or jpg?- I verified this behaviour with irfanview (image | information , used colors). As gif as an export-option is not available, how can I limit the number of used colors in the exported raster-files. reducing later in irfanview is not an option, because colors are also changed (e.g. replaced, dithered,...) not only eliminated.
I use QGIS 2.18.13 64bit under windows 10