Mikoviny

This plugin is saving pictures used in the posts from other sites (ctr+c & ctr+v) to own server and add to media library.
<h4>How to use this plugin</h4>
<ul>
<li>Just copy paste picture to post/page from other web page. By saving post/page all used pictures from other web pages download and save to your own server. Pictures are automatic added to media library. There are no setting by this plugin.</li>
<li>Now I noticed that pictures are adding twice and don?t know if it?s bug or some collision with other plugin… and have no time for now… 🙁</li>
</ul>

WP Photo Downloader

This plugin is saving pictures used in the posts from other sites (ctr+c & ctr+v) to own server and add to media library.

Stefano Lissa

Comment Image enables blog readers to attach an image while leaving their comments. 
Supported formats are JPG, PNG, GIF.
Uploaded images are inserted below the comment text as thumbnail (of configurable max dimensions) and linked to the original pictures.
File selection field can be injected automatically or added manually.
Original pictures and their thumbnails are stored in a separate folder for easy management.
See the official <a href="http://www.satollo.net/plugins/comment-image" rel="nofollow ugc">Comment Image</a> page for more.
Other plugins by Stefano Lissa:
<ul>
<li><a href="https://www.satollo.net/plugins/hyper-cache" rel="nofollow ugc">Hyper Cache</a></li>
<li><a href="https://www.thenewsletterplugin.com" rel="nofollow ugc">Newsletter</a></li>
<li><a href="https://www.satollo.net/plugins/header-footer" rel="nofollow ugc">Header and Footer</a></li>
<li><a href="https://www.satollo.net/plugins/thumbnails" rel="nofollow ugc">Thumbnails</a></li>
<li><a href="http://www.satollo.net/plugins/include-me" rel="nofollow ugc">Include Me</a></li>
</ul>

Comment Image

Enable readers to attach an image to their comments.

WP Photo Downloader vs Comment Image