setImageSize.js

setImageSize(width, height){
  if (this.props.width && !this.props.height) {
    this.setState({
      width: this.props.width, 
      height: height * (this.props.width / width)
    });
  } else if (!this.props.width && this.props.height) {
    this.setState({
      width: width * (this.props.height / height),
      height: this.props.height
    });
  } else {
    this.setState({
      width: width,
      height: height
    });
  }
}