Pete

Note: Obsolete since WordPress 4.4
<a href="https://core.trac.wordpress.org/ticket/32230" rel="nofollow ugc">This feature has been added into the core of WordPress 4.4</a>. You can now export your attachments by going to Tools->Export and select ‘Media’ as the export type.
Original Description
WP Attachment Export allows you to export your media library into a WordPress eXtended RSS or WXR file. You can then use the Tools->Import function in another WordPress installation to import the media library.
<h4>Issues / Bug reporting</h4>
Found a bug? Please use the issue tracker at <a href="https://github.com/thehelvetian/wp-attachment-export/issues" rel="nofollow ugc">https://github.com/thehelvetian/wp-attachment-export/issues</a>
<h3>Usage</h3>
User <a href="https://wordpress.org/support/profile/philho" rel="ugc">PhiLho</a> has put together a good summary on how to use the plugin at <a href="https://wordpress.org/support/topic/good-but-could-use-more-explanations" rel="ugc">https://wordpress.org/support/topic/good-but-could-use-more-explanations</a>. Thanks PhiLho!

WP Attachment Export

works perfectly.

Exports only posts of type 'attachment', i.e. your media library

Aesqe

“File Gallery” extends WordPress’ media (attachments) capabilities 
by adding a new gallery shortcode handler with templating support, 
a new interface for attachment handling when editing posts, and much 
more… Here’s the full list of features:
Features:
<ol>
<li>multiple galleries per post with custom attachment order</li>
<li>a flexible templating system (PHP, CSS, JS) – choose a different 
template for each gallery, even within the same post (4 templates 
included with plugin)</li>
<li>simple, easy to use UI with drag and drop sorting shows attachment 
thumbnails beneath text editor: everything attachments-related is on 
the same screen you’re editing your post on</li>
<li>fully integrated with the visual editor (tinyMCE) – click on the 
[gallery] placeholder image and change any option in the File 
Gallery metabox – changes will be applied instantly</li>
<li>settings page extends the default media settings page</li>
<li>attach copies of items from media library to current post (copies 
data only, not the file)</li>
<li>copy all attachments from another post</li>
<li>unattach (detach) items from current post</li>
<li>media tags = tag your attachments and then use those tags to choose 
which attachments you want to display in your gallery or to filter 
your media library items.</li>
<li>custom fields for attachments</li>
<li>gallery pagination</li>
<li>different background colors for items in media library depending 
on their status = completely unattached (white), attached to other 
posts (red), or attached to current post (yellow)</li>
<li>compatible with “WordPress Mobile Edition”, “Media Tags” and 
“WPML Multilingual CMS” plugins </li>
<li>basic caching of gallery output and frequent queries (transients)</li>
<li>please see the help file for complete list of features</li>
</ol>
<h3>More info</h3>
This plugin uses icons from the awesome famfamfam Silk icon set by 
Mark James. 
“Silk” can be found at: http://famfamfam.com/lab/icons/silk/
Plugin settings are integrated into media settings page.
Help file is included, you’ll find it in the “help” subfolder.
<h3>Translation Credits</h3>
Hebrew: 
* Maor Barazany – http://www.maorb.info/
French: 
* Jean-Michel Meyer – http://www.li-an.fr/wpplugins/
Italian: 
* Pietro Palli – http://ppal.li/ 
* Francesco Canovi – http://www.blackstudio.it/
Arabic: 
* Wassem Mansour – http://www.sanapix.com
Lithuanian: 
* Vincent G – http://www.Host1Free.com
Polish: 
* Michał Budzik – http://www.mindborn.pl/en/
<h3>Contributors</h3>
Greg Haddow (https://github.com/shaddowgh/) 
Josh Eaton (https://github.com/jjeaton/) 
Andrea Baccega (https://github.com/vekexasia)
<h3>Thanks goes out to…</h3>
<ul>
<li>All the contributors, translators, and people leaving comments, 
bug reports and suggestions on the official page and in the 
WordPress.org forums</li>
</ul>
<h3>Plans for the next versions</h3>
sooner:
<ul>
<li>manage media tags for all selected attachments</li>
<li>audio and video preview on editing screens</li>
</ul>
later:
<ul>
<li>phpdoc all the functions</li>
<li>more detailed description for file_gallery_shortcode function 
(what can be used in ‘orderby’, what do ‘columns’ mean) for beginner programmers</li>
<li>yoxview lightbox http://www.yellow-llama.com/yoxview-gallery-wordpress-plugin/</li>
</ul>
maybe:
<ul>
<li>show attachments’ Custom Fields in the main page of Media Library (custom column)</li>
<li>media library sort by file size or picture dimensions</li>
</ul>
probably not, but who knows:
<ul>
<li>watermarking – probably in another plugin…</li>
<li>when detaching / deleting attachments, just remove them from DOM 
without refreshing the entire file gallery box, but take care of 
originals and copies</li>
</ul>
And thank you for reading this 🙂
aesqe

File Gallery

File Gallery extends WordPress media (attachments) capabilities 
by adding a new gallery shortcode handler with templating support 
(and much more).

WP Attachment Export vs File Gallery