Fabio M. Giacomini

This plugin adds a new field in every post, where you can write a text that will be inserted in the related meta tag, located in the head section.
The main options page of the plugin, provides you with a default text area, where you can insert a default description that will appear in case the field in post page is empty.

Single Post Meta Description

The easiest way to add in every post page a different meta description tag, located in html head.

CongBom

Generate most common meta tags to your WordPress site.
Open Graph (og) tag via post content and featured image:
<pre><code><meta property="og:url" content="..." />
<meta property="og:type" content="..." />
<meta property="og:title"content="..." />
<meta property="og:description" content="..." />
<meta property="og:image" content="..." />
</code></pre>
Meta description tag via post content or excerpt:
<pre><code><meta name="description" content="..." />
</code></pre>

Meta Tags Generator

It assumes that the theme's screenshot is in .png format. For smaller file size reason, I prefer using .jpg images for my theme's screenshots.

To set the record straight, .png is the preferred format, although other image formats are allowed. This is a direct quote from the Codex pages:

"Note that optionally, .jpg, .jpeg, and .gif are also valid extensions and file formats for the screenshot (though not recommended)." 

Other than that, this plugin is refreshingly small in size, and that's a good thing.

Almost there!

Automatic generate meta tags. Let your WordPress site optimize with Search engine & Social sharing.

Single Post Meta Description vs Meta Tags Generator