Board Thread:Questions and Answers/@comment-26009760-20150426233247/@comment-14600979-20150426235418

If it's a port, then you probably just want the backgrounds. Get that and draw it as 16x16 tiles, discard the repeated ones, and make the map with MAPED.

You could also just keep the backgrounds as GRPs, of course. That would still be less than 100-some GRP files, but the accuracy is doubtful.