No, you can then change it for the next image you load. What it is doing is building an alpha mask, so you tell it that its green, load the image it builds the mask with green as the mask colour, then you tell it the mask colour is cyan, and it loads the next image and builds the mask with the colour cyan etc
What I tend to do is load the image as a pixmap, find the colour of the top left pixel, kill the pixmap, set the mask colour to the colour I just found, then load the image back in as an image. (I dont really do this, but that explains it easyer)
What I tend to do is load the image as a pixmap, find the colour of the top left pixel, kill the pixmap, set the mask colour to the colour I just found, then load the image back in as an image. (I dont really do this, but that explains it easyer)