     }
 }
 
-extension UInt8: PixelType {
+extension UInt8 {
     typealias SummableI = Int
     typealias SummableF = Float
     typealias SummableD = Double

    }
}

extension Double: PixelType {
    typealias SummableI = Double
    typealias SummableF = Double
    typealias SummableD = Double

    return GenericRGBA<T>(red: lhs.red + rhs.red, green: lhs.green + rhs.green, blue: lhs.blue + rhs.blue, alpha: lhs.alpha + rhs.alpha)
}

extension RGBA {
    internal typealias SummableI = GenericRGBA<Int>
    internal typealias SummableF = GenericRGBA<Float>
    internal typealias SummableD = GenericRGBA<Double>
