Python Flask update render_template

I us memcached from python to stock two datas (state) I use flask to create a webserver quickly. My goal is to recover these data with memcached and update to my flask template

mc = memcache.Client(['127.0.0.1:11211'], debug=0)
app = Flask(__name__)

def updateH():
    state = mc.get("wc_h")
    if state:
        return "yes.png"
    else:
        return "no.png"

def updateF():
    state = mc.get("wc_f")
    if state:
        return "yes.png"
    else:
        return "no.png"

@app.route('/')
def index():    
    return render_template('index.html', hstate = updateH(), fstate = updateF())

if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0')
app = Flask(__name__)

This work perfectly but I'm forced to reaload the page to update visual data.. (img src in my case) Sorry for my english. Thx