Subscribed topic doesn't call callback function

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Hi, I'm trying to get an image from the topic "/camera/image/compressed", however my attempts at doing this are not successful.

int main(int argc, char **argv)
{
    ros::init(argc, argv, "image_listener");
    ros::NodeHandle nh;
    cv::namedWindow("view");
    cv::startWindowThread();
    ros::Subscriber sub = nh.subscribe("/camera/image/compressed", 1, imageCallback);
    ros::spin();
    cv::destroyWindow("view");

    return 0;
}

void imageCallback(const sensor_msgs::ImageConstPtr& msg)
{
    std::cout << "Hello?" << std::endl;
    try
    {

        Mat img = cv::imdecode(msg->data, 1);
        std::cout << img.size << " | " << img.cols << " | " << img.rows << std::endl;
        cv::Mat image = cv::imdecode(cv::Mat(msg->data),1);//convert compressed image data to cv::Mat
        cv::imshow("view", image);
        cv::waitKey(10);
    }
    catch (cv_bridge::Exception& e)
    {
        ROS_ERROR("Could not convert to image!");
    }
}

When I look at the console after running the code the console remains empty not a single "Hello?" is seen, this leads me to believe the callback function is never called.

Also this window pops up but stays empty:

However, the node is publishing images because in rqt_image_view_ImageView I have a constant updating image:

What am I doing wrong?