code: func (opts *Options) SelectImage() string {
  	switch {
  	case opts.UseCanary:
  		return defaultImage + ":canary"
  	case opts.ImageSpec == "":
  		if version.BuildMetadata == "unreleased" {
  			return defaultImage + ":canary"
  		}
  		return fmt.Sprintf("%s:%s", defaultImage, version.Version)
  	default:
  		return opts.ImageSpec
  	}
  }
docs: // SelectImage returns the image according to whether UseCanary is true or not