Separate background into two layers.

 * A white background
 * The main graphic itself with an alpha channel.

The white was removed best I could, but there are white edges left
behind as artefacts of anti-aliasing.
Add hi-res logo export with transparent background.
Improve fireball edges by re-aliasing the edges with the alpha channel.

Before, a white edge was visible if you were observant enough.
Regenerate hi-res logo only graphic with alpha background.

Much better.