Update (moderncv v2.0)
With moderncv v2.0, the command to be patched is no more \maketitle but \makehead and the length to be changed is now \makeheaddetailswidth, so the correct patches for this version are
\patchcmd{\makehead}
{\hfil}
{\hspace*{0.15\textwidth}}
{}
{}
\patchcmd{\makehead}
{\setlength{\makeheaddetailswidth}{0.8\textwidth}}
{\setlength{\makeheaddetailswidth}{0.67\textwidth}}
{}
{}
\patchcmd{\makehead}
{\\[2.5em]}
{\hfil\raisebox{-.7cm}{\framebox{\includegraphics[width=\@photowidth]{\@photo}}}\\[2.5em]}
{}
{}
Original answer (works with older versions of moderncv)
Add the following lines in your preamble
\patchcmd{\maketitle}
{\hfil}
{\hspace*{0.15\textwidth}}
{}
{}
\patchcmd{\maketitle}
{\setlength{\maketitlewidth}{0.8\textwidth}}
{\setlength{\maketitlewidth}{0.67\textwidth}}
{}
{}
\patchcmd{\maketitle}
{\\[2.5em]}
{\hfil\raisebox{-.7cm}{\framebox{\includegraphics[width=\@photowidth]{\@photo}}}\\[2.5em]}
{}
{}
and, to insert the picture, use
\photo[64pt][0.4pt]{picture}
MWE:
\documentclass[11pt,a4paper,sans]{moderncv}
\moderncvstyle{banking}
\moderncvcolor{blue}
\usepackage[utf8]{inputenc}
\usepackage[scale=0.75]{geometry}
\patchcmd{\maketitle}
{\hfil}
{\hspace*{0.15\textwidth}}
{}
{}
\patchcmd{\maketitle}
{\setlength{\maketitlewidth}{0.8\textwidth}}
{\setlength{\maketitlewidth}{0.67\textwidth}}
{}
{}
\patchcmd{\maketitle}
{\\[2.5em]}
{\hfil\raisebox{-.7cm}{\framebox{\includegraphics[width=\@photowidth]{\@photo}}}\\[2.5em]}
{}
{}
% personal data
\name{John}{Doe}
\title{Resumé title}
\address{street and number}{postcode city}{country}
\phone[mobile]{+1~(234)~567~890}
\phone[fixed]{+2~(345)~678~901}
\phone[fax]{+3~(456)~789~012}
\email{john@doe.org}
\homepage{www.johndoe.com}
\social[linkedin]{john.doe}
\social[twitter]{jdoe}
\social[github]{jdoe}
\extrainfo{additional information}
\photo[64pt][0.4pt]{picture}
\begin{document}
\makecvtitle
\end{document}
Output:

\patchcmdremove\hfil. If it is not enough, substitute it with\hspace*{-15pt}and adjust-15ptto your needs. You can also adjust-.7cmin\raiseboxto adjust the vertical placement. – karlkoeller Jan 16 '14 at 16:24\setlength{\fboxrule}{\@photoframewidth}before the\framebox, this respects any given border width. Thanks for the patch anyways :) – resi Jul 27 '17 at 18:11