NuWEB

Nusprite plugin allows you to generate sprite images from featured images of posts and get CSS rules with PHP.
<h3>Features</h3>
<ul>
<li>Choice in image source (feature image or custom field)</li>
<li>Versioning system for long term file caching</li>
</ul>
nusprite.pot file available

Nusprite

Sprite image generator. PHP methods are available in order to get positioning of each element and write CSS rules.

Creato

Simply upload your icons individually to your theme’s “images/csprite” folder.
Go to WordPress Dashboard > Tools > CSprite > Rebuild to rebuild the sprite.
CSprite will do all the hard work of combining all the images into a single graphic.
It will create all the classes for you in the enqueued stylesheet.
You can then simply use the sprite in your theme like this:
<div class="csprite csprite-creatomatic_logo"></div>
It will name the classes according to the image names, so make sure that they are unique.
Read more about this plugin at http://www.creatomatic.co.uk/csprite-automatic-image-sprite-tool-wordpress/

CSprite

The automatic image sprite generator for WordPress

Nusprite vs CSprite