WantedPoster implements `ISignage`, and has a `publicuintimageCrc` field. With minimal hacks to SignArtist, I was able to load custom images into wanted posters via the `/sil` command.

Would it be possible to get this officially added?

P.S. It seems that wanted posters are 1024x1024, which requires upping SignArtist's maximum allowed image size config setting to 1.5MB.