Should I be using premultiplied alpha? Reading Tom Forsyth's [article](http://home.comcast.net/~tom_forsyth/blog.wiki.html#%5b%5bPremultiplied%20alpha%5d%5d) it seems a nobrainer. Premultiplied alpha (AKA additive blending) is superior in every sense.  

However, premultiplied alpha seems to have one major drawback, it's not well supported with tools.

Do you/have you used premultiplied alpha?

How is the tool support?

In particular, I don't think gimp will edit premultiplied alpha images well. Are there any gimp plugins to export premultiplied alpha? How about an external tool?