Afraid not. People can either request here/my forum or at vb.org for a background colour modification. Had I saved these out as fully transparent images the edging on the images would appear jaggy and low quality. The previews are saved to a white matte because that's the background colour that the majority of people use though people are more than free to request. ;)
An example on a brief article I wrote will explain it better. (below)
Saving that perfect graphic
So you've downloaded one of the database sets, Applied it on your forum, and found that there's white jaggy edging showing around that graphic? That's because it wasn't saved out at full transparency. There is a very good reason for this. As some, if not all database sets contain curvy transparent areas, if saved at full transparency they would look jaggy and of low quality on any forum. It's fine if that graphic doesn't contain curved edges, I can then save at full transparency as it will not have any affect on sets lacking that curved edge.
As the screenshot shows
(Below) you will notice the quality difference. That is why I won't save out the database graphics at full transparency. I always opt (and always will) for the matte drop down menu option. Although I choose white as the background colour, I am aware that not everyones forum is white, or that the graphic/set they picked is being applied onto a white background. This is why we have a database modifications area so that they can get that set correctly modified/saved out specifically for their/your forums background colour.
If you find that the database set you downloaded contains a white jaggy border. You can start a topic and request for a modification for that graphic/set in the
appropriate area (link removed), enclosing all details by conforming to the guidelines in that section.