Email processing Gulp config

gistfile1.js

var gulp = require("gulp"),
    slim = require("gulp-slim"),
    concatCss = require('gulp-concat-css'),
    uncss = require('gulp-uncss'),
    stripCssComments = require('gulp-strip-css-comments'),
    processhtml = require('gulp-processhtml'),
    smoosher = require('gulp-smoosher'),
    premailer = require('gulp-premailer'),
    htmlmin = require('gulp-htmlmin'),
    jpegoptim = require('imagemin-jpegoptim'),
    pngquant = require('imagemin-pngquant'),
    optipng = require('imagemin-optipng');

gulp.task('slim', function(){
  var stream = gulp.src("./src/*.slim")
    .pipe(slim({
      pretty: true,
      format: 'xhtml'
    }))
    .pipe(gulp.dest("./src/"));
  return stream;
});

gulp.task('css', ['slim'], function() {
  var stream = gulp.src("src/css/*.css")
    .pipe(concatCss("styles.css"))
    .pipe(uncss({
      html: ['src/*.html']
    }))
    .pipe(stripCssComments())
    .pipe(gulp.dest('build'));
  return stream;
});

gulp.task('styles', ['css'], function () {
  gulp.src('src/*.html')
    .pipe(processhtml())
    .pipe(smoosher())
    .pipe(gulp.dest('dist'));
});

gulp.task('email', ['styles'], function () {
  gulp.src('dist/*.html')
    .pipe(premailer())
    .pipe(htmlmin({
      keepClosingSlash: true,
      collapseWhitespace: true,
      preserveLineBreaks: true,
      removeComments: true
    }))
    .pipe(gulp.dest('dist'));
});

gulp.task('images', function () {
  gulp.src('src/images/**/*.{png,jpg,jpeg,gif}')
    .pipe(pngquant({quality: '65-80', speed: 4}))
    .pipe(optipng({optimizationLevel: 3}))
    .pipe(jpegoptim({max: 70}))
    .pipe(gulp.dest('dist/images'));
});

gulp.task('watch', function() {
  gulp.watch('src/*.slim', ['email']);
  gulp.watch('src/css/*.css', ['email']);
});

gulp.task('default', ['email', 'watch']);