func `$`[S, IsArray](img: ImageObject[S, IsArray]): string

proc `[]`(image: Image; x, y: uint32): auto

proc `[]`(image: ImageArray; layer, x, y: uint32): auto

proc `[]=`[T](image: var Image[T]; x, y: uint32; value: T)

proc `[]=`[T](image: var ImageArray[T]; layer, x, y: uint32; value: T)

proc addImage[T: PixelType](imageArray: var ImageArray[T]; image: sink Image[T])

func copy[S, T](img: ImageObject[S, T]): ImageObject[S, T]

proc loadImageData[T: PixelType](pngData: string | seq[uint8]): tuple[
    width: uint32, height: uint32, data: seq[T]]