In the latest entry to his blog, Mikko Koppanen shows how to take the power of Imagick and harness it to check and see what sorts of colors an image contains:

The code in the example reduces the image colors to 10, then discards all but one pixel of every color and then creates the palettes out of those colors. This might not be the most accurate way to do this, but at least it's fast.

His code makes three different "palettes" from the image - average, dark and light - and outputs them as a range of colored boxes for each all of the three palettes. Examples of the output are also included in the post.

On BarelyFitz Designs, there's a handy tutorial that's been posted to help developers out there combine the powers of PHP and CSS to form a sort of color management system for their site.

They follow the steps to making a CSS file with PHP - generate the header and output the CSS - as well as examples of its usage. They create a range of colors based around a central one, five levels in either direction. The file they've created to accomplish this is also available for download.