Double Viewer WordPress Plugin is an easy-driven and comfy app which allows you to compare two different images in one slider.

Updates:
[30 September 2013]
Added ability to view unlimited number of slides in one Double Viewer
Added a text field for displaying information on each slider
Added buttons of switching between slides
Added an option to change size of viewer according to size of screen
Refined an admin panel
Features:
Working in WordPress 3.6
Working in all of main browsers and mobile devices
Possible to set any colors for cursor and line and to change the size of cursor and line
Possible to add widgets to Sidebar
Possible to create any number of double-viewers and set it on your pages using the shortcode
Several types of mouse controlling
Easily manageable back-end
Test at your mobile device

I hope this Double Viewer WordPress will be useful for you and your site.