Empty space after adding an image [duplicate]

Question

This question already has an answer here:

• Should I use center or centering for figures and tables? 1 answer

After adding an image I have an empty space. How can it be reduced? I used \FloatBarrier. But it did not worked.

% Following copied by Marc van Dongen from comment from OP.
\documentclass[12pt,a4paper,oneside]{report}
   \usepackage{fancyhdr}
   \usepackage{graphicx}
   \usepackage{placeins}
   \begin{document}
   \FloatBarrier
   \subsection{ddd}
      \begin{figure}[ht]
         \begin{center}
            \includegraphics[width=9cm,height=5.5cm]{sss.jpg}
         \end{center}
         \begin{center}
            \caption[ddd ]{ ddd }
         \end{center}
      \end{figure}
      \FloatBarrier
      In English, the word datum is still used in the general
       sense of "an item given".
      In cartography, geography, nuclear magnetic
\end{document}

Answer 1

You should avoid using the center environment to align your content. Specifically, use \centering to centre content within a floating environment like figure:

\documentclass[12pt,a4paper,oneside]{report}
\usepackage{graphicx}
\begin{document}
\subsection{ddd}
\begin{figure}[ht]
  \begin{center}
    \includegraphics[width=9cm,height=5.5cm]{example-image-a}
  \end{center}
  \begin{center}
    \caption[ddd ]{ ddd }
  \end{center}
\end{figure}
In English, the word datum is still used in the general
 sense of ``an item given.''
In cartography, geography, nuclear magnetic.

\newpage

\subsection{ddd}
\begin{figure}[ht]
  \centering
  \includegraphics[width=9cm,height=5.5cm]{example-image-a}
  \caption[ddd ]{ ddd }
\end{figure}
In English, the word datum is still used in the general
 sense of ``an item given.''
In cartography, geography, nuclear magnetic.
\end{document}

See Should I use center or \centering for figures and tables?.

Answer 2

Apart of use of \centering of Werner answer, you can also control the space below the captions with \belowcaptionskip (for example \belowcaptionskip-1em) in the preamble or adjust manually a particular space with a negative \vspace (for example \vspace{-1cm}) in the text under the float.

However, to obtain an elegant format, simply use \centering.