inputDir = "/Users/wayne/Downloads/Eric/";
   outputDir = "/Users/wayne/Downloads/stack/";
   list = getFileList(inputDir);
   //setBatchMode(true);
   for (k=0; k<list.length; k++) {
      open(inputDir +list[k]);
      run ("Subtract Background...", "rolling=100");
      run( "Orange Hot", "");
      saveAs("Jpeg", outputDir +list[k]);
      close();
}