Gif = ref object
  frames*: seq[Image]
  intervals*: seq[float32]
  duration*: float32

gifSignatures = ["GIF87a", "GIF89a"]

proc decodeGif(data: string): Gif {....raises: [PixieError], tags: [RootEffect].}

proc decodeGifDimensions(data: string): ImageDimensions {....raises: [PixieError],
    tags: [].}

proc newImage(gif: Gif): Image {....raises: [], tags: [].}