static void savePNG(BufferedImage img, File file) ctex {
  File tempFile = new File(file.getPath() + "_temp");
  CriticalAction ca = beginCriticalAction("Save " + f2s(file));
  try {
    ImageIO.write(img, "png", mkdirsFor(tempFile));
    file.delete();
    tempFile.renameTo(file);
  } finally {
    ca.done();
  }
}

// gotta love convenience & program-smartness
static void savePNG(File etc file, BufferedImage img) {
  savePNG(img, file);
}

ifclass RGBImage
static void savePNG(File file, RGBImage img) {
  savePNG(file, img.getBufferedImage());
}
endif