code: func (i *Image) Resize(spec string) (*Image, error) {
  	return i.doWithImageConfig("resize", spec, func(src image.Image, conf imageConfig) (image.Image, error) {
  		return imaging.Resize(src, conf.Width, conf.Height, conf.Filter), nil
  	})
  }
docs: // Resize resizes the image to the specified width and height using the specified resampling
  // filter and returns the transformed image. If one of width or height is 0, the image aspect
  // ratio is preserved.