06-22-2016, 12:04 PM
The icon is indeed just the center part of the image. The border, background, and text all get added automatically by the site. If you need a visual though, take a look at some of the existing icons. You can open the image in a new tab or window to see exactly what's expected. For the most part though, you're spot-on - the character on an appropriately sized transparent background, PNG format, is perfect.