Centering all images

Question

Possible Duplicate:
How can I automatically center image?

How can I align center all picture :

\begin{figure}‎
‎‎\centering‎  % I want do not use this line for every images
‎\includegraphics[]{a‎}‎‎
‎\caption{dsafkjtfdgkajhg‎}‎‎
‎\end{figure}‎‎