Ability to change Backgroud Color from Black to White

[melchorc]

If you don't want to open the source code. Can you add an option to change the background color from black to white? What I'm trying to achieve is, I want to use this to convert scanned book pages and make it print friendly. I need to remove those black snudges. I can use Image Magick but it's more convenient if your application can do that.