Function writeImage

writeImage(image: Image, filename: string): void
Writes a LifeHash image to a PNG file.

Port of write_image() from lifehash.cpp lines 174-186 and PNGWriter class from png-writer.hpp.
Parameters
- image: Image
  The LifeHash image to write
- filename: string
  The output filename
Returns void
Example
```
import { makeFromUtf8 } from "@bcts/lifehash";

const image = makeFromUtf8("Hello");
writeImage(image, "Hello.png");
```
- Defined in tools/lifehash-cli/src/png-writer.ts:32