Hi Gerd, Here is an example where I combine several img's, for instance to merge Lambertus img tiles into one big map or to add contour lines or hiking routes: http://www.openfietsmap.nl/downloads/osm_combi I have to filter out the index img's and overview img's with several batch files, so if mkgmap can recognize them automatically, the scripts would be more simple.
Yes, I agree this will lead to problems and it would be better if mkgmap also recognize and skips processing the overview img and other index img's (*_mdr.img) before compiling img tiles.
it might be there if you execute mkgmap twice, once with *.osm as input, next time with *.img I am not sure yet if the other combiner options like --gmapsupp, --index etc. have problems with this.
Gerd