diff --git a/cfg/AddingImages.cfg b/cfg/AddingImages.cfg
index 5b378e5a..27f58c01 100755
--- a/cfg/AddingImages.cfg
+++ b/cfg/AddingImages.cfg
@@ -9,7 +9,7 @@ gen = ParameterGenerator()
 gen.add("use_camera_info", bool_t, 0, "Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.", True)
 
 gen.add("alpha", double_t, 0, "weight of the first array elements.", 0.5, 0.0, 1.0)
-gen.add("use_beta", bool_t, 0, "True: Automatically set beta weight as 1 - alpha, False: Use user defined beta weight", False)
+gen.add("auto_beta", bool_t, 0, "True: Automatically set beta weight as 1 - alpha, False: Use user defined beta weight", True)
 gen.add("beta", double_t, 0, "weight of the second array elements.", 0.5, 0.0, 1.0)
 gen.add("gamma", double_t, 0, "scalar added to each sum.", 0, 0, 255)
 
diff --git a/src/nodelet/adding_images_nodelet.cpp b/src/nodelet/adding_images_nodelet.cpp
index 309d37b1..7dae86f2 100644
--- a/src/nodelet/adding_images_nodelet.cpp
+++ b/src/nodelet/adding_images_nodelet.cpp
@@ -155,11 +155,11 @@ namespace adding_images {
       boost::mutex::scoped_lock lock(mutex_);
       config_ = config;
       alpha_ = config.alpha;
-      if ( config.use_beta ) {
-        beta_ = config.beta;
-      } else {
+      if ( config.auto_beta ) {
         beta_ = 1.0 - alpha_;
         config.beta = beta_;
+      } else {
+        beta_ = config.beta;
       }
       gamma_ = config.gamma;
     }
@@ -174,6 +174,11 @@ namespace adding_images {
           cv_bridge::toCvShare(image_msg1, image_msg1->encoding)->image;
         cv::Mat image2 =
           cv_bridge::toCvShare(image_msg2, image_msg2->encoding)->image;
+        if (image_msg1->encoding != image_msg2->encoding) {
+          NODELET_ERROR("Encoding of input images must be same: %s, %s",
+                        image_msg1->encoding.c_str(), image_msg2->encoding.c_str());
+          return;
+        }
 
         cv::Mat result_image;
         cv::addWeighted(image1, alpha_, image2, beta_, gamma_, result_image);