Open a new file, quite big, and use the ‘Floodfill’ bucket (near the bottom of the menu on the left) to fill the image with the colour you want your ‘outline’ to be.
Now select another colour to use, and click the ‘Text’ tool, right under the ‘Floodfill’ option, and change your settings on the bar near the top of the screen to these (if you’re using a small font uncheck the ‘Antialias’ box):
Click your image, then type in the text you want and press ‘Apply’. The text should show up with a dotted flashing border around it.
At the top of the screen go to ‘Selections’ > ‘Modify’ > ‘Expand’. If any other boxes come up just click ‘Ok’. If it’s a big font expand by two or three instead of 1 to make it look better. When you’re happy with it, press ‘Ok’.
Click the ‘Pan Tool’ (the white arrow) at the top of the left menu, and right click inside the dotted flashing lines. Then ‘Copy’ and ‘Paste as new image’, then save.