# 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}


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}