ImageShack Offloader is a plugin that allows you to use ImageShack as a free CDN for your images, with maximum convenience.

It has a friendly settings page where you can set up all the details, such as which image sizes should be offloaded and in what order.

You don’t have to modifiy your posts: Post content with images that are offloaded is filtered by the plugin, replacing image URLs automatically.

You can use the default WP interface for uploading images: You don’t need to go to the ImageShack site at all.

You have a backup of your images on your server: After offloading an image, this plugin doesn’t delete the copy from your server.

You can download it from WordPress Extend.