The \caption command also has an optional parameter, \caption[''short'']{''long''} which is used for the List of Tables or List of Figures.
Typically the short description is for the caption listing, and the long description will be placed beside the figure or table. This is particularly useful if the caption is long, and only a "one-liner" is desired in the figure/table listing.
Here is an example of this usage:
\documentclass{article}
\usepackage{graphicx}
\begin{document}
\listoffigures
\begin{figure}[!ht]
\centering
\includegraphics[width=0.5\textwidth]{example-image-a}
\caption[Image A]{Image A : describe it here.}
\end{figure}
\begin{figure}[!ht]
\centering
\includegraphics[width=0.5\textwidth]{example-image-b}
\caption[Image B]{Image B : describe it here.}
\end{figure}
\end{document}
Hope this helps. You can find more about \caption here.
\caption[short]{very very long}– touhami Aug 21 '16 at 12:38