使用resize mode cover
并将宽度设置为ScreenWidth/2您可以使用Dimensions组件重新设置屏幕宽度
//Get screen width using Dimensions component
var {width} = Dimensions.get('window');
//....
//In image style
image:{
width: width * 0.5
}
//In render function
<Image resizeMode = 'cover' style = {styles.image}/>
Edit adding overflow
//add overflow : visible
<Image resizeMode = 'cover' style = {[styles.image,{overflow: 'visible'}]}/>