Rewrite, maintenance and feature improvmeents to a macOS normal map generator which I wrote back in 2009 or so.
NormalMappr supports interactive normal map generation on single images:
NormalMappr also supports batch operation on multiple images files, or recursively on directories. In batch mode, NormalMappr will attempt to filter out ("exclude") images which don't appear to be bump maps. This way you can safely just drag in a folder containing a bunch of textures, and reasonably expect that just your bumpmaps will be processed. Users can move excluded images into the batch, and visa versa for false positives.
