Problems integrating OpenCV with ROS Indigo

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I am trying to build a simple program to start working with OpenCV with ROS Indigo; however, whenever I try to build the code (catkin_make) the build fails and returns " undefined reference to 'cv::imread(cv::String const&, int)' " and so on for all the other OpenCV functions. This makes it impossible for me to build and run my test program for ROS and I'm at a loss for how to continue. I've quoted the program and CMakeLists.txt below.

OpenCV 3.1 is installed and has been successfully compiled using g++ in the terminal. The OS is LinuxMint 17.3

Program imgloader.cpp:

#include <ros/ros.h>
#include <cv_bridge/cv_bridge.h>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/opencv.hpp>
#include <iostream>

using namespace cv; using namespace std;

int main(int argc, const char** argv){  
Mat img = imread("img.jpeg", CV_LOAD_IMAGE_UNCHANGED);
if(img.empty()){
       cout << "Image cannot be found or opened..." << endl;
       return -1;
}
namedWindow("MyWindow", CV_WINDOW_AUTOSIZE);
imshow("MyWindow", img);
waitKey(0);
destroyWind("MyWindow");
return 0;
}

The following has been added to the CMakeLists.txt file for the package "opencvtest"

find_package(OpenCV REQUIRED) 
include_directories(include ${catkin_INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS}) 
add_executable(imgloader src/imgloader.cpp)
target_link_libraries(imgloader ${catkin_LIBRARIES} ${OpenCV_LIBRARIES}) 
add_dependencies(imgloader opencvtest)

And the following dependency has been added:

<build_depend>opencv2</build_depend>
<run_depend>opencv2</run_depend>

What do I need to add or do to make my package build?