added Images exercise

exercises/06-images/go.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"code.google.com/p/go-tour/pic"
+	"image"
+	"image/color"
+)
+
+type Image struct {
+	w, h int
+}
+
+func (i *Image) ColorModel() color.Model {
+	return color.RGBAModel
+}
+
+func (i *Image) Bounds() image.Rectangle {
+	return image.Rect(0, 0, i.w, i.h)
+}
+
+func (i *Image) At(x, y int) color.Color {
+	v := uint8(x & y)
+	return color.RGBA{v, v, 255, 255}
+}
+
+func main() {
+	m := &Image{256, 512}
+	pic.ShowImage(m)
+}