gulp.task('images', function() {
  return gulp.src('./screens/**/*.png')
  // Works correctly with or without my memo plugin when imagemin is removed.
  .pipe(memo('_memo/gulp-memo.json'))
  // Only moves a single file to dest unless this is commented out.
  .pipe(imagemin())
  // Makes the file containing a single folder near the end of the stream (but curiously, not the last file in the stream) unless imagemin is removed.
  .pipe(gulp.dest('./cdn/img'));
});