title: How to determine that input is an image in MATLAB?
body: <p>So title fully described whole question.</p>
  
  <pre><code>if ischar(image_sorce)
      img = imread(image_sorce);
  else
      if ismatrix(image_sorce)
        img = image_sorce; end;
  end;
  </code></pre>
  
  <p>But ismatrix returns 0 when input variable <code>image_source</code> is created with imread.</p>