Problem with vertical space in enumerate environment

I have a problem regarding the vertical space between \item and an image. I use the following code and the image doesn't move vertical as it should. Why is that? And how can I fix it?

\documentclass[12pt]{article}

\usepackage{graphicx}

\begin{document}

\begin{enumerate}
\item

\begin{enumerate}
\item

\vspace{0.3cm}

\includegraphics[scale=0.7]{2.2.a.png}

\end{enumerate}

\end{enumerate}

\end{document}


Edit I: Also I had deleted by mistake the \usepackage{graphicx} and it still compiled without error! How is that possible and why?

• ! Undefined control sequence. l.13 \includegraphics Apr 2, 2014 at 19:03
• Sorry I deleted it by mistake while copying it.
Apr 2, 2014 at 19:25
• You can edit the question to fix it, add draft at same time as no one has an image of that name, Apr 2, 2014 at 19:27
• I edited it. You can change it with a random image in order to compile it.
Apr 2, 2014 at 19:30

\documentclass[12pt]{article}

\begin{document}

\begin{enumerate}
\item

\begin{enumerate}
\item

\end{enumerate}

\end{enumerate}

\end{document}

• Why doesn't work without any fixes? What's the problem?