[Tex/LaTex] Top padding inside tabular when using parbox

Question

I need to fake a caption under an image, since you can't use figure/caption inside tabular/longtable environments (afaik).
The data inside the table are generated dynamically so I don't know the height of the image from time to time. I know the width though.

So, to fake the caption I use a parbox inside a table cell to encapsulate the image and caption.

Finally, the problem: I need more padding in the top of the cell. In the following minimal example the rule clamps to the top of the cell with no padding at all.

\documentclass[10pt,a4paper]{article}
\usepackage{longtable}
\begin{document}
\begin{longtable}{| p{105 mm} |}
\hline
HEADER \\
\hline
\parbox[t]{10cm}{
\rule{100mm}{50mm}
Fake caption
\strut}\\
\hline
\end{longtable}
\end{document}

Possible solutions include removing parbox and use something else.
The important part here is that I want to fake the caption under the image and I need it to be in an tabular environment.

Edit1: Added vertical borders to the example code.

Answer 1

You can add \vspace{.5\baselineskip} soon after \parbox[t]{10cm}{. Adjust .5\baselineskip suitably.

\documentclass[10pt,a4paper]{article}
\usepackage{longtable}
\begin{document}
\begin{longtable}{| p{105 mm} |}
\hline
HEADER \\
\hline
\parbox[t]{10cm}{
\vspace{.5\baselineskip}  %% this line added
\rule{100mm}{50mm}
Fake caption
\strut}\\
\hline
\end{longtable}
\end{document}