This plugin allows you to add and image as background of posts, pages or custom post type in general (in the same way as a thumbnail).
<ul>
<li>This is a rewrite of my old plugin <a href="https://wordpress.org/plugins/post-background/" rel="ugc">Post Background</a> which I do not have access anymore. *</li>
</ul>

WP Post Background

This plugin allows you to add and image as background of posts, pages or custom post type in general (in the same way as a thumbnail).

Andy Charrington

Easily add background options on a per page/post basis.
Currently the plugin includes the following features-
<ul>
<li>Add a background image</li>
<li>Options for vertical & horizontal repeating</li>
<li>Fade out the bottom edge of your background image</li>
<li>Choose background colour</li>
<li>Child pages of a page with a custom background will inherit the parent page background settings.</li>
</ul>

Background Per Page

Background Per Page allows you to set a custom background per page (or post) as well as set up a default background for all other pages/posts.

WP Post Background vs Background Per Page