Wlecome to RPTools!
(Thank you for the compliment.
We certainly like it.
Your image probably has a bunch of blank space around it. MapTool uses the image size
to determine how to size the token so you will either need to either:
(a) Use TokenTool and create a new token (which won't look good for a top-down token), or
(b) Open the image in a paint program and remove all of the blank area around the image.
If the size isn't off by very much, you can also use the token editor dialog's Config tab to resize the image. Position the mouse over the image in the bottom-left corner of the dialog and use the mouse wheel to resize it. You can also left-click-drag to position it within the allowable space.