I used this: http://www.inkscapeforum.com/viewtopic.php" onclick="readonly();return false;"http://mirror.net16.net/SO00732_.svg" class="postlink">http://mirror.net16.net/SO00732_.svg

That SVG file has (implicitly, by default) width="100%", height="100%" and preserveAspectRatio="xMidYMid". This means that when displayed it should fill the viewing area, as far as is possible while preserving the aspect ratio. So the image doesn't have a specific size, but reporting the size as 1 x 1 is very misleading (particularly as the image isn't even square). Reporting the size as 1758 x 1623, as Inkscape 0.47 does, makes more sense. If you want to file a bug report for gThumb or nautilus, point them to sections 5.1.2, 7.7 and 7.8 of the SVG 1.0 (or 1.1) spec.

If you would like WMFtoSVG to produce SVG files with a fixed width and height, you can use the -w and -h command line options, as described in the documentation. E.g., -w 500 -h 500 will produce an SVG file that is at most 500x500. Or, alternatively, use the --write-size command line option.

Thanks! I can now see the preview in nautilus.