Using multicol for framed figure

Question

I have some figures in my article. I want the figures to be framed. I managed to do this with the figure and floatrow packages. But I have a problem of changing the size of the frame, such that I have to reduce the figure size for it to fit in the frame. Then I cam across Colorbox under graphix hasn't the same width, from which I adapted the following mwe:

\documentclass[b5paper,11pt,fleqn,leqno,parskip=full]{article}
\usepackage{graphicx}
\usepackage[english,dutch]{babel}
\usepackage{multicol}
\usepackage{xcolor}
\graphicspath{ {../Images} }

\begin{document}
\begin{multicols}{3}
\noindent\parbox[t]{1.2\linewidth}{%
\fcolorbox{gray}{gray}{\includegraphics[width=2.5\linewidth]{../Images/precip_corr.jpg}
  \parbox{\dimexpr\linewidth-2\fboxsep-2\fboxrule\relax}{\color{white}%
  \raggedright{Areas of Significant El Nino-Related Precip Anomalies.\\ \small source: Ropelewski and Halpert.}
  }%
}%
}
\end{multicols}
\end{document}

This example works for me, except I want the caption below the figure. Moreover I do not understand the various arguments, changing by trial and error has not been useful, except:

1.2 in \noindent\parbox[t]{1.2 and \includegraphics[width=2.5.

I hope someone can help me:

a) get the caption below, if possible b) explain

{3} in \begin{multicols}{3}

[t] in \noindent\parbox[t]

-2 in \parbox{\dimexpr\linewidth-2\fboxsep-2

Thanks in anticipation.

Answer 1

I think you can safely switch to using mdframed for the background, the size can be easily changed, so if that's why you had the multicols package, you can remove it.

Below is an example with a \newcommand. The color of the background is optional (default white).

Regarding your questions:

1. The number 3 in multicols denotes the number of columns the text splits into.

2. The option [t] in parbox is the text alignment, that goes:

   • [t] — text is placed at the top of the box.
   • [c] — text is centered vertically.
   • [b] — text is placed at the bottom.
   • [s] — stretch vertically. Note that the text must contain vertically stretchable space for this to work.

3. \linewidth-2 basically is removing 2 from the value of \linewidth.

---

Note: the margins have been altered to show the pages closer for this screenshot. Click the image to view it better.

Output

Code

\documentclass[b5paper,11pt,fleqn,leqno]{article} % parskip=full was unused
\usepackage{graphicx}
\usepackage[english,dutch]{babel}
\usepackage{cleveref} % clever referencing that adds "fig.", etc, automatically
\usepackage{xcolor}
\usepackage{mdframed} % required for drawing the background + line color
\usepackage{float} % needed to use [H]

\newcommand\bfig[4][white]{
  \begin{figure}[H]
    \begin{mdframed}[linecolor=#1,backgroundcolor=#1]
    \centering
    \includegraphics[width=\textwidth,height=\dimexpr\textheight-4\baselineskip-\abovecaptionskip-\belowcaptionskip\relax,keepaspectratio]{#2}
    \caption[caption]{#3}\label{#4}
    \vspace{10pt}
    \end{mdframed}
  \end{figure}
}

\begin{document}

\bfig{example-image-a}{Areas of Significant El Nino-Related Precip Anomalies.\\\hspace{\textwidth}\small Source: Ropelewski and Halpert.}{imagea}

As showed in \cref{imagea}, A is the best letter.

\bfig[gray]{example-image-b}{Areas of Significant El Nino-Related Precip Anomalies.\\\hspace{\textwidth}\tiny Source: Ropelewski and Halpert.}{imageb}

While \cref{imageb}, well, not really...
\end{document}