title: could not find a writer for the specified extension in function 'cv::imwrite_'
body: <p>I am facing error while defining a function to add border in an image</p>
  <pre><code>import cv2
  
  def im_border(path: str, output: str = &quot;output.png&quot;):
                im1 = cv2.imread(path)
                border = cv2.copyMakeBorder(
                              im1, 20, 20, 20, 20, cv2.BORDER_CONSTANT, value = [128, 128, 128])
                cv2.imwrite(output, border)
  
                return None 
                
  im_border(r'C:\Users\manoj\OneDrive\Desktop\8a4c4b2b47cdcbb6d359140081f63478.jpg',r'C:\Users\manoj\OneDrive\Desktop')
  </code></pre>
  <p>Why this is giving an error
  The error is as follows -</p>
  <p>cv2.error: OpenCV(4.5.5) D:\a\opencv-python\opencv-python\opencv\modules\imgcodecs\src\loadsave.cpp:730: error: (-2:Unspecified error) could not find a writer for the specified extension in function 'cv::imwrite_'</p>