Sergey Biryukov

Allows to find all posts where a particular attachment (image, video, etc.) is used.
Adds a “Used In” column to the list view in Media Library, as well as to the attachment details modal.
Finds posts that use the image (including any of its intermediate sizes) in post content, or as a featured image. Works with custom post types too.
Inspired by a <a href="http://wptavern.com/the-problem-with-image-attachments-in-wordpress" rel="nofollow ugc">WP Tavern post</a> on image attachments.

Find Posts Using Attachment

Allows to find all posts where a particular attachment is used.

cybio

Gallery Widget is a simple plugin that let you show the latest/random images of 
the wordpress media gallery inside a widget, directly in your templates (it is 
possible to choose some categories to be included/excluded) or in posts/pages 
using a shortcode (see faq on how to use them).
For more information on how to use this plugin see <a href="http://blog.splash.de/plugins/" rel="nofollow ugc">splash 😉</a>
Please report bugs and/or feature-request to the ticket-system: <a href="http://trac.splash.de/gallerywidget" rel="nofollow ugc">TicketSystem/Wiki</a>. 
For Support, please use the <a href="http://board.splash.de/forumdisplay.php?f=102" rel="nofollow ugc">forum</a>. 
Latest development news: <a href="http://twitter.com/cybiox9" rel="nofollow ugc">Twitter</a>.

Gallery Widget

Simple widget to show the latest/random images of the WordPress media library as a Widget, using a shortcode or directly with a php-function.

Find Posts Using Attachment vs Gallery Widget