I've added some basic functionality such as
- full picture on thumb click
- display of current folder
- display of the number of files available
Also there are options to exclude svgz files(since opera fails to render them) and raster files. And there's a tool to fix files without the xml prolog and viewbox attribute. It will add prolog and if there were width and height attributes on the svg element, it will generate the viewBox.
That's it for now. When a bug gets fixed i'll publish the widget on http://widgets.opera.com
I'd be glad to see some feedback!