glowrocks

For posts and pages with no featured image, and no images associated with the entry, a random image is selected from the media library and set as the featured image.
The plugin currently does not test for images associated with the entry.
Instead, install and run the Easy Add Thumbnail plugin (https://wordpress.org/plugins/easy-add-thumbnail/).
That plugin will set the featured image on all entries that both have no featured image AND have an image associated with the post.
What is left is entries without featured images and without any images.
This plugin provides a random image from the sites media library so that index pages look more interesting (and possibly confusing/humorous depending on which image is randomly selected.)
There is a notice at the bottom of each post the plugin has updated noting the random image. In a future release, this note will be optional via the standard user interface, but for now one has to edit the plugin and remove the last “filter” line. This notice is not displayed if the plugin is removed.

Random Auto Featured Image

For posts/pages with no featured image, & no images associated with the entry, a random image is selected from media library & set as featured image.

JohnnyPea

Automatic adding of random thumbnails to the posts without featured image based on images from media gallery.
Are you missing something or isn’t it working as expected ? I am open to suggestions to improve the plugin !
Thanks the <a href="http://wp.sk/" rel="nofollow ugc">Slovak WordPress community</a> and <a href="http://www.webikon.sk/" rel="nofollow ugc">webikon.sk</a> for the support. You can find free support for WordPress related stuff on <a href="http://www.techforum.sk/" rel="nofollow ugc">Techforum.sk</a>. For more information about me check out my <a href="http://johnnypea.wp.sk/" rel="nofollow ugc">personal page</a>.

Random Post Thumbnail

Easy way to add random featured images to your posts.

Random Auto Featured Image vs Random Post Thumbnail