# Location of EPS file while inserting into LaTeX file

\begin{figure}
\centering
\includegraphics[scale=.87]{Plot_Left_Right.eps}
\caption{Banknote Left vs Right}
\end{figure}

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When using graphicx, you don't need to specify the file extension. A list of default extensions are added depending on the driver used. See Graphics extensions and their order of inclusion. –  Werner Sep 17 '12 at 17:59

In your given snippet the image has to be in the same directory of your tex file.
In my opinion it is better to use a directory images for example. Then you have to include the relative path images/ in the call of \includegraphics:
\includegraphics[scale=.87]{images/Plot_Left_Right.eps}