LaTeX文档插入png图片

1. Use the graphicx package with the following command in the preamble:

         \usepackage{graphicx}     

   Yes, there are others but this is the best and most widely used.
2. Insert the figure: using the figure environment as follows:

   \begin{figure}[htb]        

    \center{\includegraphics[width=5cm]  {pic-name.png}}        

    \caption{\label{1} My figure.  An example of a cool figure}      

    \end{figure}