carestad

If your site is depending on posts to have their thumbnail images set, this is the plugin for you. Also makes it possible 
to require tags in every new post.
When trying to save a post without at thumbnail or tags and when activated, the user will get a warning and the post will 
be saved as a draft instead.

Post Requirements

This plugin allows you to require posts to have thumbnail set and/or tags.

dauidus

Requirements Checklist allows admins to require content to be entered before a page/post can be published. Currently it supports requirements for the following areas on the add/edit screen:
<ul>
<li>title</li>
<li>WYSIWYG editor</li>
<li>featured image</li>
<li>excerpt</li>
<li>categories (allows for min and max number of categories, 1-3 & infinite)</li>
<li>tags (allows for min and max number of tags, 1-5, 7, 10, 15, 25 & infinite)</li>
<li>up to 5 custom taxonomies per post type (allows for min and max number of categories/tags, as detailed above)</li>
<li>support for WordPress SEO by Yoast (Focus Keyword and Meta Description fields)</li>
<li>support for All In One SEO Pack (Title, Description and Keywords fields)</li>
</ul>
Requirements Checklist uses OOP standards to add options only for those metaboxes which are supported for each post type and to execute code only on those pages where it is needed. It works especially well for sites with many custom post types that require content to be entered in a specific way (ie. when a post type requires a custom excerpt or when the absence of a featured image will break the intended look of a post). Think of any theme or plugin that supports an image slider powered by a featured image, and you can surely see where this plugin will come in handy.
To be clear, Requirements Checklist does absolutely nothing to the front-end of your site. It simply forces certain types of data to be added to the add/edit page/post admin screen in order for that content to be published or updated. If content requirements are not met, a draft can still be saved.
Requirements Checklist works with multisite networks and allows users to define settings on a per-site basis.
As of version 2.3.1, Requirements Checklist has support for localization. To translate this plugin into your language, please contact the author.
Translators: 
French – Jean-Michel Meyer (Li-An)

Requirements Checklist

Just what I needed, does the job perfectly.
Didn't notice any bugs.



Excellent plugin

Allows admins to require content to be entered before a page/post can be published.

Post Requirements vs Requirements Checklist