Alexandru Vornicescu

If you want to resize featured images (post thumbnails) on the fly for your posts automatically then this plugin can help you.
To take effect just open a post or page and all featured images in that post will be resized to a normal size.
This plugin can be very useful after a theme install.
It can be an alternative for Regenerate Thumbnails plugin.
I think this plugin is better because you will not need to wait before all images are resized for all different sizes, just for images that are need to resize.
The plugin will keep the original copy of all image files.

Resize Post Thumbnails

This plugin is very useful and time-saving! Works fast and doesn't need any extra steps.

Best alternative to Regenerate Thumbnails

This plugin will resize post thumbnails on the fly.

giuliopanda

Bulk images allows you to optimize images uploaded to wordpress without creating unnecessary copies of the upload folder!
Warning: the plugin overwrites images. 
Later the plugin tries to update links to images in articles and metadata, but it may happen that these need to be recreated. Other plugins that optimize images generally duplicate all images and create complex overlays to manage their systems. This plugin is designed to keep sites with the original wordpress structure, but it may require a little more work later. But I believe this work is rewarded by better final quality. 
If anything goes wrong anyway you can go back with the restore button.
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<li>You can resize all images with just one click.</li>
<li>You can convert images to webp.</li>
<li>You can optimize images by choosing quality.</li>
<li>You can change the name of the images</li>
<li>It is optimized to speed up the bulk process. 1000 images take a few minutes on a normal server.</li>
<li>You can enable the option to optimize images when uploaded to the server.</li>
<li>Allows you to decide the maximum size of the images and the quality in which they should be compressed.</li>
<li>Adds to media-library (list version) the possibility to select the images to be optimized.</li>
<li>Through graphics it allows you to monitor the status of the images on the server.</li>
<li>Ability to use specific hooks to customize optimization options.</li>
<li>You can restore and go back to the original images.</li>
<li>
You can remove the original images if you have space problems.
The GitHub repo can be found at <a href="https://github.com/giuliopanda/op-bulk-image-resizer" rel="nofollow ugc">https://github.com/giuliopanda/op-bulk-image-resizer</a>. Please use the Support tab for potential bugs, issues, or enhancement ideas.
</li>
</ul>
<h3>Credits</h3>
The Bulk image resize was started in 2021 by <a href="giuliopanda@gmail.com" rel="nofollow ugc">Giulio Pandolfelli</a>

Bulk images optimizer: Resize, optimize, convert to webp, rename …

One of the few plugins that overwrites images while keeping your website clean

Resize Post Thumbnails vs Bulk images optimizer: Resize, optimize, convert to webp, rename …