mltsy

OwnLocal

<p>This WordPress plugin allows you to choose a photo from Flickr’s collection of<br />
Creative Commons licensed photos, crop it, and use it as the header for your<br />
WordPress site.  You must setup your own Flickr API key to use it.</p>
<p>This plugin is still in development, and has only been tested with the<br />
TwentyEleven theme.  There are several features that are not implemented,<br />
including deactivating a Flickr header.  As it is my first wordpress plugin, I<br />
expect it will break for some people. If it does, please create an issue<br />
ticket in the GitHub repository, where this project is maintained:</p>
<p>https://github.com/ownlocal/flickr-header</p>
<p>Or even better – submit a pull request! 😉</p>
<h3>Usage</h3>
<p>To use the plugin, you must have a flickr API key.  Sign up for one at:<br />
http://www.flickr.com/services/apps/create/apply</p>
<p>You must decide whether you will be using the plugin for commercial or<br />
non-commercial putposes, and choose the corresponding API key.</p>
<p>Once your template is updated and you have your API key:</p>
<h3>1. Enter your API key</h3>
<h4>Option A) Regular WordPress Installation</h4>
<p>From your site’s Dashboard, go to “Appearance > Flickr Header”, enter your API key and click “Update API key”.</p>
<h4>Option B) Multisite Installation</h4>
<p>From the Network Dashboard, click “Settings > Flickr Header”, enter your API key and hit “Update Key”</p>
<h3>2. Select an image</h3>
<ol>
<li>Go to “Appearance > Flickr Header” from your site’s dashboard</li>
<li>Type a term in the search box to search for an image</li>
<li>Click on an image to select it and hit “Save Changes”</li>
<li>Adjust the crop box to your hearts desire, and hit “Update Crop”</li>
<li>Load your site, and behold the beauty… or else, submit a bug report 😉</li>
</ol>


Flickr Header

Choose a Creative Commons photo from Flickr, crop it, and use it as your header. Attribution is added automatically!

jmarreros

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


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.

Flickr Header vs External URL Featured Image