lots of vision stuff from Ben
diff --git a/aos/atom_code/camera/Buffers.h b/aos/atom_code/camera/Buffers.h
index 7f1206d..c145b1b 100644
--- a/aos/atom_code/camera/Buffers.h
+++ b/aos/atom_code/camera/Buffers.h
@@ -83,7 +83,7 @@
   void Release();
 
   // How big images are.
-  static const int32_t kWidth = 640, kHeight = 480;
+  static const int32_t kWidth = 320, kHeight = 240;
 };
 
 } // namespace camera
diff --git a/aos/build/externals.gyp b/aos/build/externals.gyp
index eb19cd0..c30b81e 100644
--- a/aos/build/externals.gyp
+++ b/aos/build/externals.gyp
@@ -60,6 +60,16 @@
       },
     },
     {
+      'target_name': 'opencv',
+      'type': 'none',
+      'link_settings': {
+        'libraries': [
+          '-lopencv_core',
+          '-lopencv_imgproc',
+        ],
+      },
+    },
+    {
 # TODO(brians) convert this to downloading + building
       'target_name': 'libevent',
       'type': 'none',