gulpfile.js

var
    gulp = require('gulp'),
    imagemin = require('gulp-imagemin'),
    imageResize = require('gulp-image-resize'),
    cache = require('gulp-cache')
changed = require('gulp-changed')
;


gulp.task('default', ['images', 'thumbs', '2k']);

gulp.task('images', function () {
    return gulp.src('templates/static/img/banners/*.+(png|jpg|jpeg|gif|svg)')
        .pipe(imagemin({
            interlaced: true
        }))
        .pipe(gulp.dest('templates/static/img/banners/min/'))
});

gulp.task('thumbs', function () {
    gulp.src('templates/static/img/banners/*.{png,jpg,jpeg}')
        .pipe(changed('templates/static/img/banners/thumbs/'))
        .pipe(imageResize({width: 600}))
        .pipe(gulp.dest('templates/static/img/banners/thumbs/'));
});

gulp.task('2k', function () {
    gulp.src('templates/static/img/banners/*.{png,jpg,jpeg}')
        .pipe(changed('templates/static/img/banners/sm/'))
        .pipe(imageResize({width: 2000}))
        .pipe(gulp.dest('templates/static/img/banners/sm/'));
});

// gulp.task('default', ['images', 'thumbnails'], function (){ console.log ('running default task'); });