App.js

import React, { Component } from 'react';
import { Colors } from 'react-native/Libraries/NewAppScreen';
import ImagePicker from 'react-native-image-picker';
import { StyleSheet,View,Text,TouchableOpacity,Image } from 'react-native';

export default class App extends Component {
    state = {
      imagePicked: null,
    };
    constructor(props) {
      super(props);
      this.pickphoto = this.pickphoto.bind(this);
    }
    
  pickphoto(){
      const options = {
        quality: 1.0,
        maxWidth: 500,
        maxHeight: 500,
        storageOptions: {
        skipBackup: true,
        },
      };

      ImagePicker.showImagePicker(options, (response) => {
        console.log('Response = ', response);

          if (response.didCancel) {
            console.log('User cancelled photo picker');
          } else if (response.error) {
            console.log('ImagePicker Error: ', response.error);
          } else if (response.customButton) {
            console.log('User tapped custom button: ', response.customButton);
          } else {
            let source = {uri: response.uri};

            this.setState({
              imagePicked: source,
            });
        }
    });
  }

  render() {
    return (
   
        <View style={styles.body}>

            <Text style={{textAlign:'center',fontSize:20,paddingBottom:10,marginBottom:100}} >Pick Images from Camera & Gallery</Text>

         <View style={styles.mainSection}>

             <Image style={styles.image} source={this.state.imagePicked}/>

             <TouchableOpacity onPress={this.pickphoto.bind(this)} style={styles.btn}  >
                  <Text style={styles.btnText}>Pick a photo</Text>
             </TouchableOpacity>
             
         </View>
     </View>
    );
  }
};

const styles = StyleSheet.create({
  body: {
    backgroundColor: Colors.white,
    justifyContent: 'center',
    borderColor: 'black',
    borderWidth: 1,
    height: "100%" ,
    width: "100%"
  },

  mainSection: {
    alignItems: 'center',
    marginTop:10
  },

  btn: {
    width: 225,
    height: 60,
    backgroundColor: '#a29bfe',
    alignItems: 'center',
    justifyContent: 'center',
    borderRadius: 3,
    marginBottom:10
  },

  btnText: {
    textAlign: 'center',
    color: 'white',
    fontSize: 14,
    fontWeight:'bold'
  },

  image: {
    width: 400,
    height: 400,
    marginBottom:200,
  },
});