The Google Script fetches your Twitter followers and appends the list to a Google Spreadsheet. It fetch the Twitter avatar and add it to the cell using Image formula. This method was used to determine the Egg followers for any Twitter user.

function getTwitterFollowers() {

  var api = "https://api.twitter.com/1.1/followers/list.json?count=200";

  var oAuth = UrlFetchApp.addOAuthService("labnol");

  oAuth.setAccessTokenUrl("https://api.twitter.com/oauth/access_token");
  oAuth.setRequestTokenUrl("https://api.twitter.com/oauth/request_token");
  oAuth.setAuthorizationUrl("https://api.twitter.com/oauth/authorize");
  oAuth.setConsumerKey("CONSUMER_KEY");
  oAuth.setConsumerSecret("CONSUMER_SECRET");

  var result = UrlFetchApp.fetch ( api, {
    "method": "get",
    "oAuthServiceName":"labnol",
    "oAuthUseToken":"always"
  } );

  if (result.getResponseCode() == 200) {

    if ( var json = JSON.parse(result.getContentText()) ) {

      var ss = SpreadsheetApp.getActive().getActiveSheet();

      for (var u in json.users) {

        var user = json.users[u];

        ss.appendRow([
          '=image("' + user.profile_image_url + '", 4, 50, 50)' : "",
          '=hyperlink("http://twitter.com/' + user.screen_name + '","' + user.name + '")',
          user.status ? user.status.created_at : "never",
          user.created_at,
          user.statuses_count,
          user.followers_count,
          user.friends_count,
          user.url.replace(/https?:\/\/(www.)?/, "").replace(/\/$/, "") : "",
          user.location,
          user.description.replace(/\n|\r/g, " ")
        ]);

      }
    }
  }
}