There's a great free little program called TokenTool from RPTools that lets you make your own tokens quickly and easily from any image you have. In just a few seconds, I made my profile pic ("A Stark Takes the Iron Throne") into token form (of course, making the 3D LEGO model to screencap in the first place took considerably longer, but that's beside the point). Anyway, TokenTool has no install necessary. You just download a zip file, unzip it, and run the program. Not too much of a learning curve either - you just drag the image you want to use into the circle (you can adjust the size of the circle from the menu options on the sidebar, and even use your scroll wheel to adjust the size of the image to your liking).