title: serving an image with python and flask not working
body: <p>I reduced the code for this to, I think, minimum while trying to get it to work:
  The python:</p>
  
  <pre><code>#!/usr/bin/env python
  from functools import wraps
  from flask import Flask, render_template, session, request, redirect, url_for
  from flask_socketio import SocketIO, emit, join_room, leave_room, \
      close_room, rooms, disconnect
  
  
  async_mode = None
  
  app = Flask(__name__)
  app.config['SECRET_KEY'] = 'secret!'
  socketio = SocketIO(app, async_mode=async_mode)
  
  @app.route('/')
  def index():
      return render_template('index_test.html')
  
  
  if __name__ == '__main__':
      socketio.run(app, debug=True)
  </code></pre>
  
  <p>The html:</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html lang="en"&gt;
  &lt;head&gt;
      &lt;meta charset="UTF-8"&gt;
      &lt;title&gt;Title&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;img src="{{ url_for('index') }}bulboff.gif"/&gt;
      &lt;p&gt;"{{ url_for('index') }}" &lt;p&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>The image is in the static folder.</p>
  
  <p>And it gives this error:</p>
  
  <p>"GET /bulboff.gif HTTP/1.1" 404</p>
  
  <p>when the page is accessed.</p>
  
  <p>I've tried several things like setting the Flask default paths, without the url_for, etc, but, still no image.</p>
  
  <p>What am I missing?</p>