[Tex/LaTex] minipage environment with bottom-aligned

Question

I would like to make my figures with bottom-aligned, but the arrows are still in the center. Here is my code:

\begin{figure}[!ht]
\centering
\begin{minipage}[c]{0.2\textwidth}
  \includegraphics[width=1\textwidth]{dicore1.eps}
\end{minipage}
$\rightarrow$
\begin{minipage}[c]{0.2\textwidth}
 \centering
 \includegraphics[width=1\textwidth]{dicore2.eps}
\end{minipage}
$\rightarrow$
\begin{minipage}[c]{0.2\textwidth}
 \centering
\includegraphics[width=0.8\textwidth]{dicore3.eps}
\end{minipage}
$\rightarrow$
\begin{minipage}[b]{0.2\textwidth}
 \centering
\includegraphics[width=0.6\textwidth]{dicore4.eps}
\end{minipage}
\caption{A series of retractions.}
\label{fig:Retr}
\end{figure}

It strangely looked like this:

If I make all of them to be \begin{minipage}[b], then they are indeed bottom-aligned, but the arrows are also bottom aligned.

How could I solve it?

Answer 1

Another option is to change the definition of the last minipage to

\begin{minipage}[t][][b]{0.2\textwidth}

The first optional argument, t, defines the 'anchor' of the minipage, so here the top is placed on the baseline. The last optional argument, b, defines where in the minipage the content should be placed, here it is placed at the bottom.

The second optional argument, which I left empty, defines the height of the minipage. I'm not exactly sure what happens when it is left empty, I assumed it would use the natural height, but someone else would have to verify that.