gulp.task('previews', function () {
  return gulp.src('src/img/works/*.{png,jpg}')
    .pipe(responsive({
      '*': [
        {
          width: 375,
          height: 400,
          rename: {
            suffix: '_preview',
            extname: '.jpg',
          },
          crop:{
            gravity: "north"
          }
        },
        {
          rename: {
            suffix: '_full',
            extname: '.jpg',
          }
        }
      ]
    }))
    .pipe(imagemin({progressive: true}))
    .pipe(gulp.dest('public/img/works'));
});