Mateusz Krosnowski

Optisize is a powerful yet lightweight WordPress plugin designed to automatically optimize your media library. It hooks into the upload process to ensure every image you add to your site is compressed and converted to WebP, significantly improving page load speeds and SEO performance.
Key Features: 
* Automatic WebP Conversion: Automatically converts JPG, JPEG, and PNG uploads to WebP. 
* Smart Compression: Maintains high visual quality while drastically reducing file sizes. 
* Bulk Optimization: Process your existing media library with a built-in batch processing tool. 
* Easy Toggle: Quickly enable or disable optimization directly from the Media Library. 
* Content Replacement: Automatically updates post content to point to the new WebP versions of your images.

Optisize – WebP Konwerter

Automatically compresses images on upload and converts them to the modern WebP format.

nixtool

Nix Image Optimizer helps optimize your WordPress media library by converting supported image uploads to WebP automatically and giving you tools to manage existing images, generate lightweight featured images, and improve image SEO metadata.
Features:
<ul>
<li>Automatically converts new JPG, JPEG, PNG, and AVIF uploads to WebP.</li>
<li>Bulk-compresses existing Media Library images.</li>
<li>Shows compression statistics in a Media Log.</li>
<li>Adds optional watermark support before compression.</li>
<li>Generates blog-style featured images from post title, category, author name, and avatar.</li>
<li>Supports custom featured image background colors, gradients, typography, and output dimensions.</li>
<li>Auto-fills missing image ALT text and attachment descriptions from post content.</li>
<li>Includes Basic and Advanced Image SEO Metadata modes.</li>
<li>Scans and backfills existing posts with safe generated-metadata rules.</li>
<li>Includes an unused media scanner and cleaner.</li>
<li>Works with WordPress Media Library metadata and regeneration flow.</li>
</ul>
<h3>External services</h3>
This plugin can connect to the WordPress avatar system, which commonly uses Gravatar, when the Featured Image Generator is configured to include the post author’s avatar.
When the avatar option is enabled, the plugin requests the author’s avatar URL while showing the featured-image preview in the WordPress admin and while generating a featured image for a post or page. WordPress builds that avatar URL from the author’s user account email address according to the site’s normal avatar settings. The plugin downloads the avatar image from that URL so it can draw the circular author avatar into the generated featured image. If the avatar option is disabled, or if no avatar URL is available, the plugin does not request the avatar image and uses a local placeholder shape instead.
The avatar service is provided by Gravatar/Automattic: 
Terms of Service: https://wordpress.com/tos/ 
Privacy Policy: https://automattic.com/privacy/

Nix Image Optimizer

Convert images to WebP with bulk compression, media log, watermarking, image SEO, featured image generation, and unused media cleanup.

Optisize – WebP Konwerter vs Nix Image Optimizer