Background
There are several questions asking how to put a box around an image, such as question 1, question 2 and question 3.
Question
How to create a box that includes the image and the caption both. Something like as shown below:
\begin{yyyyyyyyyyyy}
\begin{figure}
\centering
\includegraphics[width=\linewidth]{xxxxxxxxx}
\caption[xxxxxxxxxxxxx]{xxxxxx}
\label{fig:base-case-constant-circulation}
\end{figure}
\end{yyyyyyyyyyyy}

\setlength{\FrameRule}{<width>}with a value of your choice. Pleace thic ocmmand in the preamble to influecne allframedenvironments in the document. Place it insidefigurebut beforeframedto only change this specific frame. – leandriis May 30 '20 at 11:44