Creating a Ping Sprite

1. Take an image of your subject in profile. The image should be in profile to match all other ping sprites in the game.

2. Open the image in GIMP.

3a. Delete the background.

3b. Make sure to catch any stray bytes. Use the "Select by Color Tool" to match against all empty/transparent pixels; this will make the lightly-colored pixels stand out.

4. Color the image. Select the image by using the "Select by Color Tool" to match exactly all the transparent pixels, and then do Select > Invert. Then paint the image white.

5. Go to Filters > Edge Detect > Difference of Gaussians. Ensure your primary color is white and your secondary color is black.

6. Be sure to use the "Merge" option. Check for any weirdly-detected edges.

6. Fine tune the filter. You may need to edit your image to smooth out the edges in order to achieve a more natural result.

7. Use the "Color to Alpha" tool to transform black into transparency.

8. Check the final image.

9. Ensure the Image is 128x128. Your vehicle sprite should take up only a small part of that.