iNexi

<p>This slider is easy to use, but powerful. It is designed to be responsive, and works perfectly with mobile devices. It can be automatically displayed on posts and pages, inserted by shortcode or PHP. The slides are pulled on each post from the attached images (gallery).</p>
<h4>Features</h4>
<ul>
<li>Automatically display slider for every post and/or page</li>
<li>Slides are created from images attached to the post/page it is displayed on (WordPress Gallery)</li>
<li>Responsive slider performs the same on every platform (desktop or mobile)</li>
<li>Fade or slide effects</li>
<li>Navigation with buttons, “dots”, keyboard, scroll-wheel, automatic timer</li>
<li>Show titles and descriptions with an overlay</li>
<li>Link individual slides to any URL</li>
<li>Show a “zoom” button to integrate with a Lightbox plugin</li>
<li>Many options available through an easy to use admin interface</li>
</ul>
<p>Please visit my homepage to submit bug reports and feature requests.</p>
<p>Plugin Homepage: <a href="http://inexi.com/wordpress" title="iNexi: WordPress Plugins" rel="nofollow ugc">iNexi.com</a></p>


Easy Gallery Slider

Responsive slider uses the images attached to a post or page. Simple to customize and configure.

kubiq

<p>Statistics say that WebP format can save over a half of the page weight without losing images quality.<br />
Convert PNG, JPG and GIF images to WebP and speed up your web, save visitors download data, make your Google ranking better.</p>
<ul>
<li><strong>automated test after plugin activation to make sure it will work on your server</strong></li>
<li><strong>works with all types of WordPress installations: domain, subdomain, subdirectory, multisite/network</strong></li>
<li><strong>works on Apache and NGiNX</strong></li>
<li><strong>image URL will be not changed</strong> so it works everywhere, in <img> src, srcset, <picture>, even in CSS backgrounds and there is no problem with cache</li>
<li><strong>original files will be not touched</strong></li>
<li>set quality of converted images</li>
<li>auto convert on upload</li>
<li>only convert image if WebP filesize is lower than original image filesize</li>
<li>bulk convert existing images to WebP ( you can choose folders )</li>
<li>bulk convert only missing images</li>
<li>works with `Fly Dynamic Image Resizer` plugin</li>
</ul>
<h3>Hooks for developers</h3>
<h4>itw_extensions</h4>
<p>Maybe you want to support also less famous JPEG extension like jpe, jfif or jif</p>
<pre><code>add_filter( 'itw_extensions', 'extra_itw_extensions', 10, 1 );
function extra_itw_extensions( $extensions ){
    $extensions[] = 'jpe';
    $extensions[] = 'jfif';
    $extensions[] = 'jif';
    return $extensions;
}
</code></pre>
<h4>itw_sizes</h4>
<p>Maybe you want to disable WebP for thumbnails</p>
<pre><code>add_filter( 'itw_sizes', 'disable_itw_sizes', 10, 2 );
function disable_itw_sizes( $sizes, $attachmentId ){
    unset( $sizes['thumbnail'] );
    return $sizes;
}
</code></pre>
<h4>itw_htaccess</h4>
<p>Maybe you want to modify htaccess rules somehow</p>
<pre><code>add_filter( 'itw_htaccess', 'modify_itw_htaccess', 10, 2 );
function modify_itw_htaccess( $rewrite_rules ){
    // do some magic here
    return $rewrite_rules;
}
</code></pre>
<h4>itw_abspath</h4>
<p>Maybe you use roots.io/bedrock or other custom folder structure</p>
<pre><code>add_filter( 'itw_abspath', 'modify_itw_abspath', 10, 2 );
function modify_itw_abspath( $abspath ){
    return trailingslashit( WP_CONTENT_DIR );
}
</code></pre>
<h4>$images_to_webp->convert_image()</h4>
<p>Maybe you want to automatically generate WebP for other plugins</p>
<pre><code>add_action( 'XXPLUGIN_image_created', 'XX_images_to_webp', 10, 2 );
function XX_images_to_webp( $image_path ){
    global $images_to_webp;
    $images_to_webp->convert_image( $image_path );
}
</code></pre>


Images to WebP

Great

Convert PNG, JPG and GIF images to WebP and speed up your web

Easy Gallery Slider vs Images to WebP