If you want to add a default featured images automatically if no featured image added in your posts and pages in your WordPress sites, then keep your close attention in this tutorial as I am going to share how to set a default fallback image for WordPress post thumbnails.
In this tutorial, I have share a WordPress plugin to set default featured image to your posts and pages.
Default featured image is a WordPress plugin to set a default featured image to posts and page.
Backend setting page of plugin.
Frontend plugin page screen.