Mikko Koppanen has another blog entry posted dealing with image manipulation with PHP and Imagick, this time it's a cool little script that lets you pick your watermark's color based on the image's background luminosity.

Usually images are watermarked using a predefined color (let's say for example "white"). How well does this actually work when you're doing the watermark on a light or even a white image? The answer is simple: not very well.

His example uses the ImagickPixelIterator to check the luminosity of the background and assigns the text a value between black and white according to the background. Complete code with usage and examples of the resulting images are included.

New on PHPit.net today is part two of their series covering working with images in PHP through the GD graphics library.

In this second part of the "Image manipulation with PHP & the GD library" article series you will learn how to resize images, create thumbnails, watermark images and more.

They start with resizing images, showing how to grab the current size and alter it to modify the output (both in a set and proportional way). With that code in place, they take the next logical step - an automatic thumbnail creator from a file upload. Finally, they show how to help protect your images using a watermark - their example is a "Image by YourWebsite.com" string of text placed on the image.

From DevShed today, there's a new tutorial on using the built-in PHP image manipulation functionality (the GD libraries) to dynamically put watermarks on your images.

PHP features a wide array of functions for image handling and manipulation. In today's article, we are going to use those functions to create an image watermarking class. This class will operate on two images: a source image and a watermark. As an optional third parameter our class will also accept an alpha value '" allowing our watermark to contain alpha transparency.

They start off with a brief summary of what the functions are and how the script will work. From there, it's all source code and examples to get the script up and working. In the end, you'll have a script you can call from an img tag in HTML and it will generate the content for you automatically...