anchor: CompressedImageData:getDimensions
  Gets the width and height of the CompressedImageData.
  width, height = CompressedImageData:getDimensions()
  width number The width of the CompressedImageData.
  height number The height of the CompressedImageData.
  width, height = CompressedImageData:getDimensions( level )
  level number A mipmap level. Must be in the range of CompressedImageData:getMipmapCount().
  width number The width of a specific mipmap level of the CompressedImageData.
  height number The height of a specific mipmap level of the CompressedImageData.