\begin{figure}[h]\centering%图片居中
\includegraphics[scale=0.9]{1.jpg}%长宽比例为原来的0.9倍
%\caption{This is an inserted JPG graphic}%位于图片下面的标题
\end{figure}
插入多个图片
\begin{figure}[htbp]
\centering
\subfigure[xx] {\includegraphics[scale=0.7]{1.jpg}}
\subfigure[yy] {\includegraphics[scale=0.7]{2.jpg}}
\caption{(a)Analogy n=1;(b)Analogy n=2}
\end{figure}