ArcVieh

You can select images from media Library in the Widgets backend that will be shown on your Page. You can enter a size for the images.
The thumb-images will be linked to the full-sized-image. 
Requieres PHP 5!

Media Images Widget

Requieres PHP 5! You can select images from media Library in the Widgets backend that will be shown on your Page.

Asiqur Rahman

With the help of this plugin, you can become hassle-free from downloading and re-uploading images from hosted elsewhere to your site.
The GL Import External Images plugin for WordPress is designed to facilitate downloading and inserting images directly into your WP Media Library from external URLs, streamlining the process of importing media content. This plugin enhances user efficiency by allowing seamless integration of external images, thereby improving content management workflows. Be a better online citizen: avoid image hot-linking with ease!
<h4>Features</h4>
<ul>
<li>Easily download images from external URLs directly into your WordPress Media Library.</li>
<li>After successful uploading, you can select or edit (like caption, title, alt, description) the image.</li>
<li>Full integration with WordPress Media Library – including creation of thumbnail images.</li>
<li>Simplifies the process of adding external images to your website and saves you time.</li>
<li>Saves time by automating the image import process.</li>
<li>Lightweight and code written following WordPress coding standards.</li>
</ul>
Like this plugin? Please consider <a href="https://wordpress.org/support/plugin/gl-import-external-images/reviews/" rel="ugc">leaving a 5-star review</a>
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GL Import External Images

Import and insert images to WordPress Media Library from external URLs.

Media Images Widget vs GL Import External Images