title: When I add image in my Latex file with TexMaker in windows, I got an error
body: <p>when I add image in my Latex file with TexMaker in windows, I got an error. My code is following:</p>
  
  <pre><code>\begin{figure}[hbtp]
  \centering
  \includegraphics[scale=1]{first1.png}
  \caption{iamgeTitle}
  \end{figure}
  </code></pre>
  
  <p>show error: undefined control sequence \includegraphics</p>
  
  <p>after that when I try to add 
      \usepackage{graphicx}
  show error: Can be used only in preamble.</p>
  
  <p>I googled it for solve the problem but failed. How can I solved the problem.</p>