Nico

<a href="http://nextgenthemes.com/plugins/regenerate-thumbnails-reminder/" rel="nofollow ugc">Plugin Page</a>
A small reminder in your admin area every time a image setting was changed (in media options, through a theme or plugin)
You most likely want to regenerate the thumbnails after this plugin reminds you to do so, if not already done I suggest you install the most used plugin Regenerate Thumbnails for this. This plugin will offer a redirection to <a href="https://wordpress.org/plugins/regenerate-thumbnails/" rel="ugc">Regenerate Thumbnails</a> in the admins reminder notice, but you can use any other plugin/method you prefer to regenerate thumbnails, just click dismiss when the reminder shows up and then manually navigate to your preferred regenerate plugin.

Regenerate Thumbnails Reminder

Checks if your image sizes have changed or if there was a new one added, if so it reminds you to go regenerate them.

Freemius

prasadkirpekar

Image Pilot helps you compress and optimize images in WordPress to improve loading speed, reduce bandwidth, and save disk space without visible quality loss.
Whether you run a blog, portfolio, or eCommerce site, Image Pilot makes image optimization simple: 
* Compress JPG, PNG, GIF, and WEBP images from the plugin dashboard 
* Keep image quality high while reducing file size 
* Resize images to match your site layout 
* Regenerate thumbnails after theme or size changes 
* Improve Core Web Vitals and overall page performance
Image Pilot is easy to set up and provides manual, admin-triggered optimization for Media Library and upload directory images.
<h3>Image Pilot offers:</h3>
<ul>
<li>High-quality image compression without any loss in quality</li>
<li>Easy resizing of images to suit your website’s needs</li>
<li>Thumbnail regeneration to optimize all your images</li>
<li>Simple installation and user-friendly controls</li>
<li>Upgrade your website’s image optimization with our powerful WordPress plugin today!</li>
</ul>

Image Pilot – Image Compression and Optimization for WordPress

Compress and optimize WordPress images without visible quality loss. Resize images, regenerate thumbnails, and improve page speed to save bandwidth an …

Regenerate Thumbnails Reminder vs Image Pilot – Image Compression and Optimization for WordPress