This code will set the image height to auto based on the given width or vice versa.
import AuthoHeightImage from 'AuthoHeightImage';
<AuthoHeightImage
url='http://placehold.jp/300x500.png'
newWidth={300}
styles={styles.image}
/>
import AuthoHeightImage from 'AuthoHeightImage';
<AuthoHeightImage
url='http://placehold.jp/300x500.png'
newHeight={300}
styles={styles.image}
/>