gulp.task('Watch source files', () => {

    let imagesWatcher = gulp.watch('src/images/**/*.*');

    imagesWatcher.on('add', file => {

        // error
        fs.copyFile(file, 'dist/images', error => { if (error) throw error;});
    });
});

Error: EPERM: operation not permitted, copyfile `...` -> `...`