Greg - SiteOrigin

A lot of themes ship with Timthumb because it allows their users to start using the theme without rebuilding thumbnails.
Secure Image Resizer offers a far more secure alternative. It allows theme developers to rely on WordPress’ own image resizing functionality using <code>add_image_size</code> and <code>get_the_post_thumbnail</code>.
When get_the_post_thumbnail is called, Secure Image Resizer checks if the requested image size exists. If the image doesn’t exist it dynamically creates the resized version. It works in the background, with no front end functionality.
Theme developers can either bundle this plugin into their themes, or suggest that their users install it.
It also includes 2 functions <code>so_resize_custom</code> and <code>so_resize_custom_html</code> to do dynamic image resizing using Imagick. Great for theme developers.
Please Note: This is an early release of Secure Image Resizer. Please use it, try and break it and report any bugs to me support@siteorigin.com so I can quickly fix them and work towards version 1.0.

Secure Image Resizer

A very simple and secure image resizer. It adds dynamic resizing so you don't need to regenerate thumbnails when you install a new theme.

ERA404

Extends the WordPress Media Library to allow individual control over each media item size’s crop.
For those particular about their imagery…
WordPress’s Media Library already gives authors strong, intuitive organization over their web site’s images. But some users are a little more particular than others over the individual crop sizes of each media item. CropRefine is for the keen-eyed, visual types who want something fast and fastidious.
<ul>
<li>CropRefine provides quick-links from the Media Library to refine each item.</li>
<li>A full catalog of existing crops and sizes are made available for refinement.</li>
<li>If you prefer a different/better thumbnail but want to leave the other sizes untouched, CropRefine gives you that level of granularity over your imagery.</li>
<li>Packaged with cropper.js, adjusting a crop is a smooth, draggable, precise refinement experience.</li>
<li>Iterative backups are stored alongside each adjustment, so nothing is ever lost—only gained!</li>
<li>If a re-crop just won’t achieve the results you’re after, a quick-upload tool is also offered for each media item size, so that you can replace that (and only that) size.</li>
<li>No additional database is needed, no exhaustive setup process, no hidden license costs.</li>
</ul>

CropRefine

Giving you greater control over how each of your media item sizes are cropped.

Secure Image Resizer vs CropRefine