tariquesani

This plugin uses Flickr API to import comments from you Flickr photostream 
photos to a post of your choice in your WordPress Blog. It additionally 
imports the Flickr Avatar Icons and displays them as appropriate.
The Live Flickr Comment Importer Plugin features
<ul>
<li>Uses the Flickr API via the excellent phpFlickr class</li>
<li>Can automatically detect Flickr photos embedded in the post.</li>
<li>Can also use a custom field in the post to import comments thus your Photos and posts need not have the same title</li>
<li>Comments on multiple photos can be imported in a single post</li>
<li>Also imports the flickr user icons / avatars</li>
<li>The comments are imported whenever anyone sees a post where comments are to be imported</li>
<li>Allows import of even the old comments</li>
<li>Can cache the results of flickr API</li>
<li>Show thumbnails in comments</li>
<li>Allow disallow HTML in comments</li>
<li>Exclude certain pictures using custom field</li>
<li>Favorites can also be imported as comments optionally</li>
</ul>

Live Flickr Comment Importer

This plugin uses Flickr API to import comments from you Flickr photostream photos to a post of your choice in your Wordpress Blog.

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.

Live Flickr Comment Importer vs External URL Featured Image