I just finished an application and as I included a window styles manifest, my icons now look like they don't fit and as a result I now have to upgrade my icons to match. Can anyone explain to me the advancements in graphics and what packages I can use to create shiny smooth icons and graphics?

Specifically I have noticed that the icon packages I have rely on a pixel map of say 16x16 pixels and as a result the resolution is relatively poor and drawing a circle is very blocky. By contrast when I imported a 3D graphic from the web into my icon editing package I noticed that the round edges are perfectly smooth and there is no blocky pixelation effect whatsoever. This makes me think there must be a more progressive technology that avoids blocky pixelation problems altogether.