If you play games like Rainbox Six: Vegas or watch movies like Elephant Dream, you will notice the use of the so-called Bloom effect. In fact, Vegas is so bright and surrealist that this game becomes known for its Bloom overuse.
In this Graphics Dojo example, I would like to show how to render an image with the Bloom effect. This extends the previous example from Zack on making real-time glow effect. The technique: create a copy of the image, blur it, increase its brightness and then combine with the original image with a certain composition mode and opacity. Since a picture is worth a 2^10 words, I will let the following screenshot (click to enlarge) speaks for itself.
The image on the left side is the original, whereas the right one shows the result of applying Bloom. As you can see, there are few sliders where you can tweak the parameter to achieve the effect that suits your taste. Different composition modes can give (not so radically) different results as well, just play around with it.
How to get it? Just do "svn checkout svn://labs.trolltech.com/svn/graphics/dojo/bloom" followed by the usual "cd bloom && qmake && make && ./bloom". Once the main window shows up, you can also change the image by using drag-and-drop from a file on your disk or even a link from the web browser (e.g. straight from your Flickr gallery). Have fun!