Ewout

waltervos

Use this plugin to display the featured image for any post or page in your sidebar. If a featured image has been set. If no featured image has been set, the plugin tries to use the image of the parent post/page. Otherwise, no widget is displayed.

Featured Image Widget

This doesn't pull in any photos in the sidebar. The title shows up, but no images are shown. Bummers. Maybe this worked before, but it certainly doesn't now. I am using Twenty Fourteen for the theme.



Doesn't work with latest WordPress

Provides a widget that displays the featured image for a post or page. If a featured image has been set. If no featured image has been set, the plugin …

Mohamed Tawfik

This plugin let you add a featured image to a post using external URL.
You can use images from Flickr, google images… etc just in one click. 
No need to download the image and re-upload it again.
The image will be processed and thumbnails will be generated just like if you uploaded the image your self from your PC.
It is working with native and custom post types.
It is available now in two languages:
1- English 
2- Arabic
You can translate it to any languages.

WK URL 2 WP Thumb

This plugin let you add a featured image to a post using external URL.

Featured Image Widget vs WK URL 2 WP Thumb