Qrzysio

This plugin converts every uploaded JPG or PNG image into modern WebP format to improve performance and reduce file size.
Key features: 
– automatic conversion of JPG and PNG images to WebP on upload 
– correct generation of all WordPress image thumbnails 
– configurable WebP quality level 
– optional maximum image width (original images are resized before thumbnails are generated) 
– automatic removal of original JPG/PNG files to save disk space 
– full compatibility with WordPress “big image scaling” 
– automatic alt text generation based on the filename 
– filename sanitization and collision-safe renaming
All settings apply only to newly uploaded images. Existing media files are not modified.
<h3>Configuration</h3>
You can configure the plugin in Tools → Force WebP.
Available options: 
– WebP quality (0–100): controls compression quality for newly uploaded images 
– Max width (px, optional): limits the maximum width of original images before WordPress generates thumbnails (0 = disabled)
All settings affect only images uploaded after saving the configuration.

Force WebP

Say goodbye to JPG and PNG – make your site run on fast, modern WebP images.

Informatiza

Sutolix

Automatically convert all images (png and jpg) sent to the WordPress library to webp.
ATTENTION: The original images are not kept, when sending an image it will be as if you had sent a webp from the beginning.
Features include:
<ul>
<li>Set conversion quality.</li>
<li>Set the maximum width/height of images. If an image exceeds the defined value in height or width, the image will be resized to the defined maximum.</li>
<li>Ignore images that have a certain name in the file name</li>
</ul>

Webp Transformer

Convert images from library to webp and resize them during upload

Force WebP vs Webp Transformer