diff --git a/stim/image/image.h b/stim/image/image.h
index b359405..b001232 100644
--- a/stim/image/image.h
+++ b/stim/image/image.h
@@ -624,6 +624,15 @@ public:
 		return result;
 	}
 
+	//operator functions
+	image<T> operator+(image<T> rhs) {
+		size_t N = size();						//calculate the total number of values in the image
+		image<T> r(X(), Y(), C());				//allocate space for the resulting image
+		for (size_t n = 0; n < N; n++)
+			r.img[n] = img[n] + rhs.img[n];		//perform the inversion
+		return r;								//return the inverted image
+	}
+
 	image<T> srgb2lab(){
 		std::cout<<"ERROR stim::image::srgb2lab - function has been broken, re-implement."<<std::endl;
 		exit(1);
--
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