React Native rotating images (problem)

BannerAds.js

import React, { Component } from "react";
import { AppRegistry, StyleSheet, Text, View, Image } from "react-native";

import config from "../client/config.js";
import bannerimages from "../client/images/bannerads/index";

export default class BannerAds extends Component {
  constructor(props) {
    super(props);

    this.state = {
      current_index: 0,
      current_image: "../client/images/bannerads/" + config.client.bannerAds[0],
      banner_images: []
    };
  }

  componentDidMount() {
    setInterval(() => {
      this.displayRandomBannerAd();
      console.log("changed ad");
    }, 4000);
  }

  render() {
    if (config.client.bannerAds.length > 0) {
      return (
        <View style={styles.container}>
          <Image
            style={styles.bannerImage}
            source={require("../client/images/bannerads/" +
              bannerimages[this.state.current_index])}
            resizeMode="contain"
          />
          <Text>{this.state.current_image}</Text>
        </View>
      );
    }
  }

  displayRandomBannerAd = () => {
    let random_index = Math.floor(
      Math.random() * config.client.bannerAds.length
    );

    let current_image =
      "../client/images/bannerads/" + config.client.bannerAds[random_index];

    this.setState({
      current_index: random_index,
      current_image: current_image
    });
  };
}

AppRegistry.registerComponent("DisplayAnImageWithStyle", () => BannerAds);

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: "center",
    alignItems: "center",
    height: 50,
    width: "100%"
  },
  bannerImage: {
    height: 50,
    width: "100%",
    marginTop: 20
  }
});

config.js

export default {
  client: {
    bannerAds: [
      ["college-ave.png"],
      ["discover.png"],
      ["fatv.png"],
      ["ihelp.png"],
      ["inceptia.png"],
      ["pheaa.png"],
      ["pnc.png"],
      ["sallie-mae.png"]
    ]
  },
};

index.js

const bannerimages = {
  1: "college-ave.png",
  2: "discover.png",
  3: "fatv.png",
  4: "ihelp.png",
  5: "inceptia.png",
  6: "pheaa.png",
  7: "pnc.jpg",
  8: "sallie-mae.png"
};
export default bannerimages;