[Expo Camera] takePictureAsync() quality not working as expected

App.js

import React, {Component} from 'react';
import {Image, SafeAreaView, Text, TouchableOpacity, View} from 'react-native';
import {Camera, Permissions} from 'expo';

class CameraComponent extends Component {
  constructor () {
    super();
    this.state = {
      hasCameraPermission: null,
      imageSrc: null,
      type: Camera.Constants.Type.back,
    };
  }

  async componentWillMount () {
    const {status} = await Permissions.askAsync(Permissions.CAMERA);
    this.setState({hasCameraPermission: status === 'granted'});
  }

  handleSwitchCameraPress = () => {
    this.setState({
      type: this.state.type === Camera.Constants.Type.back
        ? Camera.Constants.Type.front
        : Camera.Constants.Type.back,
    });
  };

  handleTakePicturePress = async () => {
    const photo = await this.camera.takePictureAsync({base64: true, quality: 0.9});
    const imageSrc = 'data:image/jpg;base64,' + photo.base64;
    this.setState({imageSrc});
  };

  render () {
    const {hasCameraPermission, imageSrc, type} = this.state;
    if (hasCameraPermission === null) {
      return null;
    } else if (hasCameraPermission === false) {
      return <Text>No access to camera</Text>;
    }
    if (imageSrc) {
      return (
        <Image
          resizeMode = "stretch"
          source = {{uri: imageSrc}}
          style = {{flex: 1}}
        />
      );
    }
    return (
      <SafeAreaView style = {{flex: 1}}>
        <Camera
          ref = {(ref) => (this.camera = ref)}
          style = {{
            flex: 1,
            justifyContent: 'flex-end',
          }}
          type = {type}
        >
          <View style = {{
              flex: 0.1,
              flexDirection: 'row',
              justifyContent: 'space-evenly',
            }}
          >
            <TouchableOpacity onPress = {this.handleTakePicturePress}>
              <Text>{'Take picture'}</Text>
            </TouchableOpacity>
            <TouchableOpacity onPress = {this.handleSwitchCameraPress}>
              <Text>{'Rotate'}</Text>
            </TouchableOpacity>
          </View>
        </Camera>
      </SafeAreaView>
    );
  }
}

export default CameraComponent;