App.js

import React from 'react';
import { Camera, Permissions } from 'expo';
import {Alert, Button, Platform, StyleSheet, Text, TouchableOpacity, View} from 'react-native';

export default class App extends React.Component {
  state = {cameraPermissions: null, photo: null}

  async componentDidMount() {
    const { status } = await Permissions.askAsync(Permissions.CAMERA)
    this.setState({ cameraPermissions: status })
  }

  takePhoto = async () => {
    if (this.camera) {
      const photo = await this.camera.takePictureAsync()
      this.setState({ photo })
    }
  }

  uploadImageGood = async () => {
    const formData = new FormData()
    formData.append('images', {
      name: 'test.png',
      type: 'image/png',
      uri: 'https://facebook.github.io/react/logo-og.png',
    })
    await this.uploadImage(formData)
  }

  uploadImageBad = async () => {
    const { photo } = this.state
    const formData = new FormData()
    formData.append('images', {
      name: 'test.jpg',
      type: 'image/jpeg',
      uri: photo.uri,
    })
    await this.uploadImage(formData)
  }

  uploadImage = async (formData) => {
    try {
      const response = await fetch('https://www.google.com', {
        body: formData,
        method: 'POST'
      })
      Alert.alert('yes', 'worked')
      console.log(response)
    } catch (e) {
      Alert.alert('no', 'error')
      console.log(e)
    }
  }

  render() {
    const { photo, cameraPermissions } = this.state
    if(!photo && cameraPermissions === 'granted') {
      return (
        <Camera
          ref={ref => {
            this.camera = ref
          }}
          style={{ flex: 1 }}
          type='back'>
          <View
            style={{
              backgroundColor: 'transparent',
              flex: 1,
              flexDirection: 'row',
            }}>
            <TouchableOpacity
              onPress={this.takePhoto}
              style={{
                alignItems: 'center',
                alignSelf: 'flex-end',
                flex: 0.1,
              }}>
              <Text
                style={{ color: 'white', fontSize: 18 }}>
                Take Photo
              </Text>
            </TouchableOpacity>
          </View>
        </Camera>
      );
    } 
    return (
      <View style={styles.container}>
        <View>
          <Text>This button will cause an error as it tries to upload a local file</Text>
          <Button
            onPress={this.uploadImageBad}
            title="Upload local photo"
            color="#841584"
            styles={{flex:1}}
          />
          <Text>This button will not cause an error as it tries to upload a file from 'https://facebook.github.io/react/logo-og.png'</Text>
          <Button
            onPress={this.uploadImageGood}
            title="Upload remote photo"
            color="#841584"
            styles={{flex:1}}
          />
        </View>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center',
  },
});