Marko Heijnen

CodeKitchen

This plugin extend the power WordPress already have when it comes to image editing.
It currently focuses on the API side to give developers great tools to manipulate specific image sizes. 
You can do this by calling Improved_Image_Editor::register_image_size_info(). Here you can specify the following arguments: 
– quality 
– zoom 
– filters (work in progress)
It also includes the functionality of the following plugins I build: 
– Gmagick 
– Improved GD Image Editor 
– WP_Image (will be included soon)
Future plans are to build a settings page so users can select the settings per image size themself. 
I also have ideas to extend the current image editor UI with options to select the focus point per image size and build auto detection of the focus point. With every feature we add the main focus will be to build a decent API for it so at certain points it could be integrated in WordPress itself.

Improved Image Editor

Adds more image edit functionality to your WordPress installatin

Orangelab

Rickard Westerlind

Dramatically improve the quality of re-sized images by making WordPress use ImageMagick instead of standard GD image library.
Features
<ul>
<li>Preserve embedded color profile in re-sized image</li>
<li>Automatically recognize custom image sizes</li>
<li>Allow regeneration of existing images (optionally for selected image sizes only)</li>
<li>Configure image quality or use dynamically computed default value</li>
<li>Optimize different image sizes for either quality or size</li>
</ul>
Lnguages: English, French, German, Swedish, Turkish
Requires either ImageMagick binary or Imagick PHP module.
<h3>Contribute</h3>
Code repo available on https://github.com/orangelabweb/imagemagick-engine/

ImageMagick Engine

Maybe even better.  It uses ImageMagick Engine that is installed and allows me to easily regenerate all my images.

Works as advertised

The thumbnail regeneration could be a bit faster though. I have used it for longer than I can remember, at least 5 years.

Simple, functional

Improve the quality of re-sized images by replacing standard GD library with ImageMagick.

Improved Image Editor vs ImageMagick Engine