doc: link to image blog post

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5086048

doc/docs.html

@@ -97,6 +97,7 @@ Notable articles from the <a href="http://blog.golang.org/">Go Blog</a>.
 <li><a href="http://blog.golang.org/2011/01/json-and-go.html">JSON and Go</a> - using the <a href="/pkg/json/">json</a> package.</li>
 <li><a href="http://blog.golang.org/2011/03/gobs-of-data.html">Gobs of data</a> - the design and use of the <a href="/pkg/gob/">gob</a> package.</li>
 <li><a href="http://blog.golang.org/2011/09/laws-of-reflection.html">The Laws of Reflection</a> - the fundamentals of the <a href="/pkg/reflect/">reflect</a> package.</li>
+<li><a href="http://blog.golang.org/2011/09/go-image-package.html">The Go image package</a> - the fundamentals of the <a href="/pkg/image/">image</a> package.</li>
 </ul>
 
 <h3>Tools</h3>

src/pkg/image/image.go

@@ -3,6 +3,9 @@
 // license that can be found in the LICENSE file.
 
 // Package image implements a basic 2-D image library.
+//
+// See "The Go image package" for an introduction to this package:
+// http://blog.golang.org/2011/09/go-image-package.html
 package image
 
 // Config holds an image's color model and dimensions.