Trying to find alpha

    function button:setDefault( newImage )
        local defaultImage = self.default
        if ( defaultImage ) then
            defaultImage:removeSelf()
            self.default = nil
        end

        if ( newImage ) then
            defaultImage = display.newImage( newImage )
            defaultImage.alpha = .2
            button:insert( defaultImage, true )
            self.default = defaultImage
            button.alpha = .4
        end
    end