pip install opencv-python

import cv2  
  
def resize_image(input_image_path, output_image_path, width=None, height=None, inter=cv2.INTER_AREA):  
    """  
    調(diào)整圖像大小  
  
    :param input_image_path: 輸入圖像的路徑  
    :param output_image_path: 輸出圖像的路徑  
    :param width: 目標(biāo)寬度，如果為None，則不改變寬度  
    :param height: 目標(biāo)高度，如果為None，則不改變高度  
    :param inter: 插值方法，默認(rèn)為cv2.INTER_AREA（適用于縮小圖像）  
    :return: None  
    """  
    # 讀取圖像  
    image = cv2.imread(input_image_path)  
    if image is None:  
        print(f"Error: Unable to load image at {input_image_path}")  
        return  
  
    # 檢查是否指定了寬度和高度  
    if width is None and height is None:  
        print("Error: Both width and height cannot be None.")  
        return  
  
    # 如果只指定了寬度或高度，則計算另一個維度以保持圖像的寬高比  
    if width is None:  
        width = int(image.shape[1] * (height / float(image.shape[0])))  
    elif height is None:  
        height = int(image.shape[0] * (width / float(image.shape[1])))  
  
    # 調(diào)整圖像大小  
    resized_image = cv2.resize(image, (width, height), interpolation=inter)  
  
    # 顯示圖像（可選）  
    cv2.imshow('Resized Image', resized_image)  
    cv2.waitKey(0)  # 等待按鍵  
    cv2.destroyAllWindows()  
  
    # 保存圖像  
    cv2.imwrite(output_image_path, resized_image)  
  
# 使用示例  
input_image = 'path_to_your_image.jpg'  # 替換為你的圖像路徑  
output_image = 'resized_image.jpg'  
resize_image(input_image, output_image, width=640, height=480)

import cv2  
  
def resize_image_keep_aspect_ratio(input_image_path, output_image_path, max_width=None, max_height=None, inter=cv2.INTER_AREA):  
    """  
    調(diào)整圖像大小，同時保持寬高比  
  
    :param input_image_path: 輸入圖像的路徑  
    :param output_image_path: 輸出圖像的路徑  
    :param max_width: 最大寬度，如果為None，則不限制寬度  
    :param max_height: 最大高度，如果為None，則不限制高度  
    :param inter: 插值方法，默認(rèn)為cv2.INTER_AREA（適用于縮小圖像）  
    :return: None  
    """  
    # 讀取圖像  
    image = cv2.imread(input_image_path)  
    if image is None:  
        print(f"Error: Unable to load image at {input_image_path}")  
        return  
  
    # 獲取原始圖像的寬高  
    height, width = image.shape[:2]  
  
    # 計算新的尺寸  
    if max_width is None and max_height is None:  
        print("Error: Both max_width and max_height cannot be None.")  
        return  
    elif max_width is None:  
        max_width = int(width * (max_height / float(height)))  
    elif max_height is None:  
        max_height = int(height * (max_width / float(width)))  
    else:  
        # 確保寬度和高度不會超過指定的最大值，同時保持寬高比  
        ratio = min(max_width / width, max_height / height)  
        max_width = int(width * ratio)  
        max_height = int(height * ratio)  
  
    # 調(diào)整圖像大小  
    resized_image = cv2.resize(image, (max_width, max_height), interpolation=inter)  
  
    # 保存圖像  
    cv2.imwrite(output_image_path, resized_image)  
  
    # 可選：顯示圖像（注意，在生產(chǎn)環(huán)境中通常不會這樣做）  
    # cv2.imshow('Resized Image with Aspect Ratio', resized_image)  
    # cv2.waitKey(0)  
    # cv2.destroyAllWindows()  
  
# 使用示例  
input_image = 'your_image.jpg'  # 替換為你的圖像文件路徑  
output_image = 'resized_image_with_aspect_ratio.jpg'  
resize_image_keep_aspect_ratio(input_image, output_image, max_width=800)  # 只指定最大寬度  
# 或者  
# resize_image_keep_aspect_ratio(input_image, output_image, max_height=600)  # 只指定最大高度