Sorry, can't provide test at this moment - need to filter out proprietary
information.

But, if you look at the code of ExternalGraphics and Area, you may notice the
following:

// We estimate the space left in the area

            if (area.spaceLeft() < (height + spaceBefore)) {
                return Status.AREA_FULL_NONE;
            }

// ... blah

// We modify the space left in the area (addDisplaySpace changes
Area.currentHeight, and spaceLeft uses currentHeight)
            if ((spaceBefore != 0) && (this.marker == 0)) {
                area.addDisplaySpace(spaceBefore);
            }

// ... blah

// We modify the space left in the area 
            if (spaceAfter != 0) {
                area.addDisplaySpace(spaceAfter);
            }

// We use the space left in the area, but AFTER the modifications above
            if (breakBefore == BreakBefore.PAGE
                    || ((spaceBefore + imageArea.getHeight())
                        > area.spaceLeft())) {
                return Status.FORCE_PAGE_BREAK;
            }


The result is - sometimes image doesn't fit.  Reading spaceLeft into a variable
before modification and using the variable in the remaining places fixed the
problem, for me at least.