Someone could write an image editor where the project format is a directory with the source jpeg or png assets and a makefile which generates the resulting imag

Someone could write an image editor where the project format is a directory with the source jpeg or png assets and a makefile which generates the resulting image with imagemagick (or other) calls. The makefile could be easily diffable and mergeable and people wouldn't touch the binary assets (or at least wouldn't expect to diff or merge them). Brushes wouldn't be easy though. This could be handled by trivial svg or ps paths which would get rendered in the make process. This way even brush strokes could be diffable. I wounder if it would be possible to convert existing PSD files or Gimp project files into such a format.