Stefano Lissa

WordPress themes need thumbnails in different sizes and they even let the user to change those dimensions. 
But WordPress has a problem: it does not regenerates the thumbnails when new sizes are registered.
Thumbnails intercepts the request by themes or plugins to WordPress to get a specific thumbnail, generates it and caches it on disk. 
Efficiently, it produces a perfectly cropped image, with the right dimension avoiding unpleasant stretching.
Thumbnails does not modify your blog or your media library. When deactivated the blog returns to its old behavior.
The second important feature is the autoselection of featured image for post which are missing it. 
You can choose between the on the fly selection without persist it or, for better performances, to persist it once selected.
Read the <a href="https://www.satollo.net/plugins/thumbnails" rel="nofollow ugc">Thumbnails</a> official page for detailed information.
Theme developers can find instructions to use it (no code tied to Thumbnails needs to be written!).
Other plugins by Stefano Lissa:
<ul>
<li><a href="https://www.satollo.net/plugins/hyper-cache" rel="nofollow ugc">Hyper Cache</a></li>
<li><a href="https://www.thenewsletterplugin.com" rel="nofollow ugc">Newsletter</a></li>
<li><a href="https://www.satollo.net/plugins/header-footer" rel="nofollow ugc">Header and Footer</a></li>
<li><a href="https://www.satollo.net/plugins/include-me" rel="nofollow ugc">Include Me</a></li>
<li><a href="https://www.satollo.net/plugins/ads-bbpress" rel="nofollow ugc">Ads for bbPress</a></li>
</ul>
<h3>Screen shots</h3>
No screenshots are available at this time.

Thumbnails

This plugin solves my problems with the WP thumbnails, thanks Stefano!

The one that solves my problem

I re-use my post thumbnail images in various ways, so I like to upload them full size, and I need the software to resize them as needed. This plugin does exactly that for me.

It performs its magic transparently and makes my pages a lot lighter. Highly recommended.


Amazing

Autoselect the featured image and creates pixel perfect resizes on the fly without regenerate all the thumbnails.

Gagan Deep Singh

Sometimes you may want the images on your blog/site to be pixel perfect, while sometimes you may want them to be compressed to save space on the server.
This plugin allows you to select the quality of the thumbnail images generated by WordPress, as easy as that. Just go to Media Settings page and modify the Image Quality setting.
Plugin only works for new uploads, but in case you want to modify the thumbnails generated earlier, you can either use
<a href="https://wordpress.org/plugins/regenerate-thumbnails/" rel="ugc">Regenerate Thumbnails</a>
or if you are familiar with WP-CLI, then you can use this command to regenerate
<pre><code>wp media regenerate
</code></pre>
P.S. It does not change the quality of the original image that you upload, 
but only changes the quality of the thumbnails WordPress generates from that image.

Image Quality

Lets you adjust the quality of image thumbnails that WordPress generates.

Thumbnails vs Image Quality