Tech Chorus

As per the Wikipedia "alpha compositing is the process of combining an image with a background to create the appearance of partial transparency". To remove the transparency or the alpha channel:

1. Fire up GIMP
2. Open the image for which the alpha channel has to be removed
3. Click the Image menu on the image window
4. Click Flatten Image from the pull down menu
5. Save

In short, remember to flatten the image when you want to remove the alpha channel.

Quote from the GIMP docs: