You can also do it by creating the image you want, with a separate layer of alpha values, and pasting it onto a plain, rectangular 3D image.
To do this, you will need to create a DDS file - these images contain your original picture, plus a layer of alpha values that can be use to make your glow mix in with the surrounding background. You can create some suitable alpha values by simply making a greyscale version of your original picture, ramping up the brightness and making sure all of the non-glowing parts are completely white (otherwise your "solid" bits of image will be transparent.)
You can get a copy of Texture Tool from Microsoft for free to create your DDS file for you (it's part of the DX8 SDK.)
Load in your image onto a plain, 3D object. If this is the only 3D object in the scene, you can then raise or lower the ambient light values to make your object fade up and down. If you have other 3D objects in the scene, you will have to alter how that specific object reacts to the lights around it.
The benefit of this method is that you only need to create one image.
