import os
from PIL import Image

def convert_jpg_to_lowercase(folder_path):
    """
    扫描指定文件夹，将所有大写的 .JPG 文件转换为小写 .jpg 文件。
    """
    if not os.path.exists(folder_path):
        print("指定的文件夹不存在。")
        return
    
    for filename in os.listdir(folder_path):
        if filename.endswith(".JPG"):  # 仅处理 .JPG 文件
            old_path = os.path.join(folder_path, filename)
            new_filename = filename[:-4] + ".jpg"  # 修改扩展名为小写
            new_path = os.path.join(folder_path, new_filename)
            
            # 打开并重新保存图像，确保格式正确
            try:
                with Image.open(old_path) as img:
                    img.save(new_path, "JPEG")
                os.remove(old_path)  # 删除原始 .JPG 文件
                print(f"转换成功: {filename} -> {new_filename}")
            except Exception as e:
                print(f"转换失败: {filename}, 错误: {e}")

if __name__ == "__main__":
    folder = input("请输入要扫描的文件夹路径: ")
    convert_jpg_to_lowercase(folder)