utils.py

import os

def create_output_directory(directory="output"):
    """Create output directory if it doesn't exist"""
    if not os.path.exists(directory):
        os.makedirs(directory)
    return directory

def allowed_file(filename):
    """Check if file has allowed extension"""
    ALLOWED_EXTENSIONS = {'png', 'jpg', 'jpeg'}
    return '.' in filename and filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS