This plugin allows you to display all images from selected galleries created using the NextGen Gallery plugin. Images are displayed in full size.
Use shortcode [nggimages id=gallery_id] in your post/page. 
More options on “Installation” tab.

NGGImages

This plugin allows you to display all images from selected galleries created using the NextGen Gallery plugin.

aviplugins.com

Speed up your website by serving images in WebP format. This plugin will replace files in standard JPEG, PNG and GIF formats with WebP format.
After installation go to plugin settings and enable webp images. You can convert all images in Media Library or convert selected images only. The plugin will reduce the size of the image without compromising image quality.
The plugin will ditect if Webp images are supported by the client browser or not and then serve the images accordingly. 100 images can be converted per month.
<h4>Webp Converter PRO</h4>
The PRO version can convert 500 images per month. Get it for USD 2.00 Check it out <a href="https://www.aviplugins.com/webp-converter-pro/" rel="nofollow ugc">here</a>.
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Post your plugin related queries at <a href="https://www.aviplugins.com/support.php" rel="nofollow ugc">https://www.aviplugins.com/support.php</a>
</blockquote>

Webp Converter

Convert Media Library images in next-gen format and speed up your website

NGGImages vs Webp Converter