Justin Tadlock

<p>A plugin for allowing users to set a custom background on a per-post basis.  This plugin hooks into the WordPress <code>custom-background</code> theme feature and overwrites the values on single post views if the post has been given a custom background.</p>
<h3>Features</h3>
<p>This plugin creates a custom meta box on the edit post screen.  From that point, you can select a custom color and/or image.  If you select an image, you’ll be presented with additional options for how the image appears on the site.</p>
<h3>Requirements</h3>
<p>Your theme must support the core WordPress implementation of the <a href="https://codex.wordpress.org/Custom_Backgrounds" rel="nofollow ugc">Custom Backgrounds</a> theme feature.</p>


Custom Background Extended

Allows users to create a custom background on a per-post basis.

TrueFalse

<p>Plugin automatically fills the ALT attribute in HTML IMG tag on every insert a new image into the post, if it is not full.</p>
<p>Note 1. “AFI” does not attribute alt attribute to the images added to the media library.</p>
<p>Note 2. On the role of ALT attribute for the search engines read here:</p>
<ul>
<li>http://help.yandex.com/images/?id=1112581</li>
<li>http://support.google.com/webmasters/bin/answer.py?hl=en&answer=114016</li>
</ul>


ALT for images

Automatic insertion of alt attribute header-based embedded image.

Custom Background Extended vs ALT for images