[texhax] Caption spacing with \includegraphics in \figure: can I control it?

[Henry Law]

I am managing editor for a 200-page book with many imbedded JPEG images. 
  Until March I was working on it under Windows and now I'm continuing 
the work under Linux.  In each case the software used is TeXlive, emacs 
for editing and pdflatex for formatting.  The only difference was the 
level of TeXlive: 2007 before, texlive2009-20091107 now.

I formatted it yesterday and found that pagination had gone wrong, 
subtly but all-pervasively and disastrously: all our hard work in 
placing text on the pages and avoiding stray single lines has all gone 
to pot.

I've traced it to the appearance of a very slightly greater space now 
between the image and its caption: about half a vertical line I'd say. 
Do I have control over that?  I've tried Googling for an answer but it's 
hard to structure a query.

If it matters, here are relevant parts of my \includes and an example of 
the graphic inclusion statement (unchanged between Windows and Linux). 
I can't do a minimum example because the problem is the difference 
between what I get "now" and what I got "then", which none of us can 
reproduce.

\documentclass[12pt,a4paper,titlepage,openany,oneside]{book}
\pagestyle{plain}
\setlength{\textwidth}{160mm}
\setlength{\textheight}{227mm}
\setlength{\paperwidth}{210mm}
\setlength{\paperheight}{297mm}

\usepackage{amsfonts,amsmath,amssymb}
\usepackage{graphicx}
\usepackage{textcomp}
\usepackage{pst-fill}
\usepackage{wrapfig}
\usepackage{subfig}
\usepackage{ifthen}
\usepackage{color}
\usepackage{lpic}
\usepackage{hyperref}

\setlength{\parindent}{0pt}
\setlength{\parskip}{3pt}
\setcounter{chapter}{0}
\setcounter{section}{0}
\setcounter{equation}{0}
... and I don't think anything else is likely to be relevant.

\begin{figure}
\begin{center}
\mbox{\includegraphics[width=0.75\textwidth]{Graphics/gabbro_closeup.jpg}}
\end{center}
\caption[Gabbro, close up view.]{A close up view of a piece of gabbro.}
\label{fig:CloseViewPieceGabbro}
\end{figure}

-- 

Henry Law            Manchester, England