Theme Egg

Generate Thumbnail allows you to generate all thumbnails on your site. There are already some plugins available for this, but they have one thing in common: All thumbnails are regenerate in a single step. This works fine when you don’t have that many photos on your site. When you have a lot of full-size photos, the script on the server side takes a long time to run. Unfortunately the time a script is allowed to run is limited, which sets an upper limit to the number of thumbnails you can regenerate. This number depends on the server configuration and the computing power your server has available. When you get over this limit, you won’t be able to generate your thumbnails.
Why would you want to generate your thumbnails? WordPress allows you to change the size of thumbnails. This way, you can make the size of thumbnails fit the design of your website. When you change the size to fit for a new theme, all future photos you are going to upload will have this new size. Your old thumbnails won’t be resized. That’s where this plugin comes into action. After changing the image sizes, you can generate all thumbnails. But instead of telling the server to recreate all thumbnails at once, they are generate one after another. Generateing thumbnails for one photo won’t take all too long, so you won’t run into any script timeouts. Note that you still have to wait until all thumbnails have been rebuilt. If you close the page before the task is completed, you have to start all over again.
You can also select the thumbnail sizes you want to generate, so that you don’t need to recreate all images if you’ve just changed one thumbnail-size. You can also choose to only generate post thumbnails (featured images).
This plugin requires JavaScript to be enabled.

Generate Thumbnail

Generate Thumbnail allows you to generate all thumbnails at once without script timeouts on your server.

stasionok

Take some thumbnail type (called here as preset) and cast available image effects on it to get expected size or view.
With this plugin you can:
<ul>
<li>change exists preset or create new one.</li>
<li>on upload image create only enabled preset thumbnails</li>
<li>disable unused presets</li>
<li>remove disabled or extra/trash thumbnails images</li>
<li>regenerate any preset thumbnail images (after change preset as ex.)</li>
</ul>
For each preset you can cast any of available effects to change thumbnail sizes or just desaturate it or something else..

Thumbnails like in Drupal

I’m a drupal developer and i like this module. Its really looks like a drupal image style with image effects. Big thumbs up for the developer of this module. Hope to enhance and improve this in the future.

This really looks like image style of drupal

Wordpress implementation/fork of Drupal imagecache module.

Generate Thumbnail vs Thumbnails like in Drupal