til

UPLOAD_FOLDER = 'static/img'
ALLOWED_EXTENSIONS = {'png', 'jpg', 'jpeg', 'gif'}
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER

def allowed_file(filename):
    return '.' in filename and \
        filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS

if 'file' in request.files:
    file = request.files['file']

    if file and allowed_file(file.filename):
        filename = secure_filename(file.filename)
        file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))

    user_img = file.filename

else:

    user_img = "default.png"