# When I use package floatrow, option skip of package caption doesn't work

Using this piece of code, I define a demo figure and its caption,

\documentclass{book}

\usepackage{graphicx}
\usepackage{caption}
\captionsetup{
}

\begin{document}
\begin{figure}
\includegraphics{example-image-a}
\caption{Caption goes here.}
\end{figure}
\end{document}


Now, according to Axel Sommerfeldt (here), I try to align caption with left side of figure. So, after modifying the above code, I write,

\documentclass{book}

\usepackage{graphicx}
\usepackage{floatrow}
\usepackage{caption}
\captionsetup{
slc=false
}

\begin{document}
\begin{figure}
\ffigbox[\FBwidth]
{\caption{Caption goes here.}}
{\includegraphics{example-image-a}}
\end{figure}
\end{document}


And the output is pretty well. But I like to adjust the space between the figure and its caption. As the document of package caption says, option skip does it,

\documentclass{book}

\usepackage{graphicx}
\usepackage{floatrow}
\usepackage{caption}
\captionsetup{
slc=false,
skip=2cm
}

\begin{document}
\begin{figure}
\ffigbox[\FBwidth]
{\caption{Caption goes here.}}
{\includegraphics{example-image-a}}
\end{figure}
\end{document}


Unfortunately option skip makes no difference, unless I don't use package floatrow. What is the problem cause? Something like incompatibility? Is there any solution?

Use \floatsetup{captionskip=…}:

\documentclass{book}

\usepackage{graphicx}
\usepackage{floatrow}
\usepackage{caption}
\captionsetup{
slc=false,
}

\begin{document}
\begin{figure}
\floatsetup{captionskip=2cm}
\ffigbox[\FBwidth]
{\caption{Caption goes here.}}
{\includegraphics{example-image-a}}
\end{figure}
\end{document}