实际上，我在我的React Native Expo应用程序的assets文件夹中添加了一些图像。我希望当用户打开我的应用程序时，他们可以在物理设备上下载或保存这些图像。我试过很多次了，但我没有找到解决办法。我尝试了下面的代码，它在Expo Go应用程序上运行良好，但当我安装APK并打开应用程序时，它不会下载图像。你能提出一个解决方案吗？
我试过这个，它在expo go应用程序上工作，但在物理设备上不工作。

import React from 'react';
import {View, Text, Button, Image} from 'react-native'
import * as MediaLibrary from 'expo-media-library';
import {Asset} from 'expo-asset';
import { useRoute } from '@react-navigation/native';

const Test = () => {

  //Example Image Url = require('../assets/nk/myimage.jpg')
  const route = useRoute(); 
  const saveFileToMediaLibrary = async () => {
    try {
      const asset = Asset.fromModule(route.params.u);
      // Download the asset to the local file system
      await asset.downloadAsync();
      // Get the local URI of the downloaded file
      const fileUri = asset.localUri;
    // File saved successfully
      console.log('File saved to media library:', fileUri);
      
      // Save the file to the media library
      const perm = await MediaLibrary.requestPermissionsAsync();
        if (perm.status != "granted") {
          return;
        }

        try {
          const asset = await MediaLibrary.createAssetAsync(fileUri);
          console.log(asset);
          const album = await MediaLibrary.getAlbumAsync("My App Images");
          if (album == null) {
            await MediaLibrary.createAlbumAsync("My App Images", asset, false);
          } else {
            await MediaLibrary.addAssetsToAlbumAsync([asset], album, false);
          }
        } catch (e) {
          alert("Something Went Wrong..."+ e);
        }
    } catch (error) {
      alert('Error to save file in media library', fileUri);
    }
  };

  return (
    <View>
      <Button title="Download File" onPress={()=>{saveFileToMediaLibrary()}} />
      <Image 
      source={route.params.u} style={{width:100,height:100}}
      />
    </View>
  );
};
export default Test;