WebMaestro.Fr

Upload the layers of your image, and create a parallax effect !
It works great on smart devices too !
The first step is to create with your favorite picture editing software (Photoshop, GIMP…) an independent image for each ground composing your image. All these layers shall be the same size, and should be in .png format as they are meant to include transparency areas. 
Then, on your post editing page in WordPress, click the Insert Media button, and (the same way you would create a gallery) upload your layers under the Create Parallax item. Reorganise the layers if needed, from the background to the front. 
You can finally configure the animation (calibrate, invert, limit, scalar, friction), and publish !
There is <a href="http://webmaestro.fr/image-parallax-plugin-wordpress/" rel="nofollow ugc">some examples</a> on the plugin page.
It uses <a href="http://wagerfield.github.io/parallax/" rel="nofollow ugc">parallax.js</a> by Matthew Wagerfield.

Image Parallax

Create images with a parallax effect. Upload some layers, configure the animation, and publish !

marsian

Create onepage web sites or landing pages in few minutes. Custom Portfolio, Testimonial, Team and Contact Us Sections for TemplatesNext WordPress Themes. It creates easy to customize, edit sections on front page.
<a href="http://templatesnext.in/demo/" rel="nofollow ugc">Demo and documentation »</a>
Some of the features may not work properly with any other themes.
<a href="http://templatesnext.in/i-amaze-landing/" rel="nofollow ugc">Best suits with WP theme i-amaze »</a> 
<a href="http://templatesnext.in/i-one-landing/" rel="nofollow ugc">And WordPress Theme i-ONE »</a>
<h4>Theme direct download GitHub URLs :</h4>
i-one : https://github.com/TemplatesNext/i-one/archive/master.zip 
i-amaze : https://github.com/TemplatesNext/i-amaze/archive/master.zip

TemplatesNext OnePager

Creates One-Page home/landing with highly customizable and sortable sections like about us, services, portfolio, team, contact us, etc.

Image Parallax vs TemplatesNext OnePager