commit picture with Flask

Question

I tried to modify my html page already contains text and picture using flaks and python3, but it doesn't work with? Can I have some suggestions?

@app.route('/modify/>', methods=['GET', 'POST'])
def modify(id):
data = Datacontent.query.filter_by(id=id).first()
if request.method == 'POST':
    try:        
        title = request.form['title']
        content = request.form['content']
        picture = request.files['picture']

        data.title = title
        data.content = content
        data.picture = picture
        db.session.commit()
        return redirect(url_for('main', id=id))
    except:
        return redirect(url_for('main', id=id))
else:
    return render_template('modify.html', data=data)