Vincent Dubroeucq

Visit your blog posts listing page, or a single post page, and open up the WordPress customizer.
Under Tiny Thumbnail Settings, choose or upload your default image. That’s it !
Enjoy !

Tiny Default Thumbnail

Allows you to add a default featured image to posts. Just add a default image in your customizer settings !

bjovaar

Plugin for WordPress that the add thumbnail image from post in the post and page list in admin area.

Show Thumbnail Image In Admin Post / Page List

Used this plugin twice so far and it does exactly what its supposed to, it just works and its perfect what what i was trying to achieve.

Just Works!

STIAP Plugin for Wordpress that the add column for thumbnail image from post and page in the post / page list in admin area.

Tiny Default Thumbnail vs Show Thumbnail Image In Admin Post / Page List