图片的resizeMethod='resize'可以自动压缩图片，一般resizeMode用contain，

图片的高度需要动态计算：

<Image key={index} source={

{uri: number.content}} resizeMethod='auto' resizeMode='contain' style={

{flex:1,margin:0,padding:0,borderWidth:0}} onLoadStart={()=>{

Image.getSize(number.content, (width, height) => {

let ratio=width/(screenW*pixdp);//计算图片宽度折算的比率

console.log(ratio);

this.setState({totalHeight:this.state.totalHeight+height/(ratio*pixdp)});

console.log('image'+index+' height is '+ height);

});

}} />