PhotoJAR: Post Thumbnailer displays a post thumbnail. A full gallery can be displayed upon clicking the thumbnail when paired with a javascript viewer. 
PhotoJAR: Post Thumbnail requires PhotoJAR: Base.
For additional info visit <a href="http://www.jarinteractive.com/code/photojar" rel="nofollow ugc">JARinteractive</a>.

PhotoJAR: Post Thumbnail

PhotoJAR: Post Thumbnailer displays a post thumbnail.  A full gallery can be displayed upon clicking the thumbnail when paired with a javascript viewe …

Sanny Srivastava

Are you tired of manually configuring a default featured image each time you publish a page, post, or custom post type? Do you desire a default featured image to automatically serve as a thumbnail whenever you publish or update your post/page?
Look no further!
This plugin provides a convenient solution to set a default thumbnail image effortlessly for all your posts, pages, or custom post types. Select or upload any image from your media library with ease.
Access the settings via the WordPress Dashboard under Settings => “SNY Auto Featured Image” (admin menu).
Quick Setup:
<ul>
<li>Choose/upload an image from the media library.</li>
<li>Specify categories.</li>
<li>Define the post types.</li>
</ul>
Please note that this plugin automatically assigns a thumbnail when a post is published or modified, but only if the post lacks a featured image.

SNY Auto Featured Image

Automatically set a default featured image for posts, pages, or custom post types when none is assigned.

PhotoJAR: Post Thumbnail vs SNY Auto Featured Image