Bicknell Digital

Convert to AVIF and Optimise automatically converts media library images to AVIF, stripping metadata, keeping your original uploads alongside the new files and updating all of your content to reference the optimised versions. The plugin keeps featured images, site logos, page builders, widgets and other stored URLs aligned with the converted image paths.
<h4>Key features</h4>
<ul>
<li>Automatic optimisation of newly uploaded JPEG, PNG and WebP files into AVIF.</li>
<li>Bulk optimisation tool that updates every post, page, featured image and option referencing your media.</li>
<li>Adjustable quality target so you can choose the balance between fidelity and file size.</li>
<li>Optional metadata stripping and original files retained beside the AVIF copies to keep your workflow flexible.</li>
<li>British English interface copy to keep everything consistent for UK sites.</li>
</ul>

Convert to AVIF and Optimise

Convert and optimise your WordPress media library to AVIF while keeping every reference to your images in sync.

scribu

This plugin improves the gallery template by making the following tweaks:
<ol>
<li>Puts all the gallery css in a separte file, for easy customisation and faster page load.</li>
<li>Adds an id attribute to the code, so that two or more galleries can have a different number of columns and still display correctly on the same page.</li>
</ol>
Links: <a href="http://scribu.net/wordpress/improved-gallery" rel="nofollow ugc">Plugin News</a> | <a href="http://scribu.net" rel="nofollow ugc">Author’s Site</a>

Improved Gallery

Improves the built-in gallery in WordPress 2.5 and newer.

Convert to AVIF and Optimise vs Improved Gallery