Which Opencv should I use for ros Noetic?

edit

Hi, I am trying to implement OpenCV into a roscpp. I already managed to compile it successfully, even though it did not work to read and print a Image. It prints me this as a warning, which is the reason why it should not work I think. I have installed OpenCV 4.6.0

/usr/bin/ld: Warnung: libopencv_imgproc.so.406, benötigt von /usr/local/lib/libopencv_highgui.so.4.6.0, kann in Konflikt geraten mit libopencv_imgproc.so.4.2
/usr/bin/ld: Warnung: libopencv_core.so.4.2, benötigt von /usr/lib/x86_64-linux-gnu/libopencv_imgproc.so.4.2.0, kann in Konflikt geraten mit libopencv_core.so.406

CMakeLists.txt looks like this:

cmake_minimum_required(VERSION 2.8)

project(OpenCV2)

find_package(catkin REQUIRED COMPONENTS
  rospy
  roscpp
  std_msgs
  OpenCV
  sensor_msgs
  cv_bridge
)

find_package(OpenCV 4 REQUIRED )

catkin_package(
  #INCLUDE_DIRS include 
  #LIBRARIES Zajicek
  #CATKIN_DEPENDS geometry_msgs nav_msgs roscpp sensor_msgs std_msgs
  #DEPENDS system_lib
)

include_directories(
 ${catkin_INCLUDE_DIRS}
  ${OpenCV_INCLUDE_DIRS}
)

add_executable(OpenCV2 src/opencv_test2.cpp)

target_link_libraries(OpenCV2 ${catkin_LIBRARIES} ${OpenCV_LIBS} )

The code is a simple read and print code like this:

#include < opencv2/opencv.hpp>
#include < opencv2/core.hpp>
#include < opencv2/imgcodecs.hpp>
#include < opencv2/highgui.hpp>
#include < string>
#include < iostream>
#include < stdio.h>
#include " ros/ros.h"

int main(int argc, char* argv[])
{
  std::string image_path = "/home/nico/CATKINWS/src/OpenCV2/Loewe.jpg";

  // cv::Mat img= cv::imread("/home/nico/Greyscale.png", cv::IMREAD_GRAYSCALE);
  cv::Mat img;
  img = cv::imread(image_path, cv::IMREAD_COLOR);

  if (img.empty())
  {
    std::cout << "Could not read the image: " << image_path << std::endl;
    return -1;
  }
  else
  {
    cv::namedWindow("OpenCV Image", cv::WINDOW_AUTOSIZE);
    ;
    cv::imshow("Display window", img);
    cv::waitKey(0);  // Wait for a keystroke in the window
    cv::destroyAllWindows();
    return 0;
  }
}

It prints the following message:

"Could not read the image: /home/nico/CATKINWS/src/OpenCV2/Loewe.jpg"

So it get stuck in the if clause when img.empty()

I tried nearly the same code without ROS, and compiled it with cmake . and it worked as it should, So my guess is that OpenCV 4.6.0 is not compatible! So my question now is, which version should I use? Is my guess for the problem correct? and can I just download an old version and change the find package in the CMakeLists.txt to make it run, or do I have to delete the 4.6 version too? Thank you in advance!