jmarreros

This Plugin allows to use an external image as Featured Image, this can be especially useful if you house your images in another location.
This Plugin is compatible with Nelio External Featured Image Metadata, so you can reuse your data in case you want to uninstall Nelio Plugin.

External URL Featured Image

It is what I was looking for: simplicity.

$external_image = get_post_meta( $post->ID, '_dcms_eufi_img', true );

Works well for me

Use an external url image as Featured Image for your posts, pages, and other kind of post types.

lucia.intelisano

If post doesn’t have a set featured image, 
WP Autoset Featured Image Plus check if text contains an image. If yes, set this as featured image, 
if not, you can set any external url image. Otherwise, leave field empty. 
Easy and fast!
Features include:

WP Autoset Featured Image Plus

Check for an image inside text editor or use external images from anywhere as the featured image of your pages and posts.

External URL Featured Image vs WP Autoset Featured Image Plus