\documentclass[preprint,nofootinbib]{revtex4}
\usepackage{graphicx}
\usepackage{epsfig}
\usepackage{amssymb}
\usepackage{color}
\usepackage{amsmath}
\usepackage{lipsum}
\usepackage{pinlabel}
\usepackage{graphics}
\usepackage{epsf}
\usepackage{psfrag}
\usepackage{epstopdf}
\usepackage{graphicx}
\usepackage{caption}
\usepackage{epstopdf}
\begin{document}
\begin{figure}{!ht}
\centering
\includegraphics[width=0.1\textwidth]{../modified GB constrains/ziba/pic8 - Copy2.eps}
\includegraphics[width=0.1\textwidth]{../modified GB constrains/ziba/pic2- Copy2.eps}
\caption{here is an example}
\label{fig:delta}
\end{figure}
\end{document}