Python实现图片格式(Webp/PNG/JPG)批量互转及无损压缩

pip install Pillow

import os
from pathlib import Path
from PIL import Image
# 支持的图片格式
SUPPORTED_EXTENSIONS = {'.jpg', '.jpeg', '.png', '.webp', '.bmp', '.tiff', '.gif'}
# ==================== 方案 1：单个格式转换 ====================
def convert_image(input_file, output_format='jpg', quality=85, max_size=None):
    """
    转换图片格式
    参数:
        input_file: 输入图片路径
        output_format: 输出格式 'jpg'/'png'/'webp'/'bmp'
        quality: 压缩质量（1-100，仅对 jpg/webp 有效）
        max_size: 最大尺寸 (width, height) 或 None
    """
    input_path = Path(input_file)
    img = Image.open(input_path)
    # 如果需要调整大小
    if max_size:
        img.thumbnail(max_size, Image.LANCZOS)
    # 处理 RGBA → RGB（JPG 不支持透明通道）
    if output_format in ('jpg', 'jpeg', 'bmp') and img.mode == 'RGBA':
        # 白色背景替代透明
        background = Image.new('RGB', img.size, (255, 255, 255))
        background.paste(img, mask=img.split()[3])
        img = background
    # 生成输出文件名
    output_file = input_path.with_suffix(f'.{output_format}')
    # 保存参数
    save_kwargs = {}
    if output_format in ('jpg', 'jpeg'):
        save_kwargs = {'quality': quality, 'optimize': True}
    elif output_format == 'webp':
        save_kwargs = {'quality': quality, 'method': 6}
    elif output_format == 'png':
        save_kwargs = {'optimize': True}
    img.save(output_file, **save_kwargs)
    # 打印对比
    original_size = input_path.stat().st_size
    new_size = output_file.stat().st_size
    ratio = (1 - new_size / original_size) * 100
    print(f"{input_path.name} ({original_size / 1024:.1f}KB) → "
          f"{output_file.name} ({new_size / 1024:.1f}KB) "
          f"[{'+' if ratio < 0 else '-'}{abs(ratio):.1f}%]")
    return output_file
# ==================== 方案 2：批量转换 ====================
def batch_convert_folder(input_dir, output_dir, output_format='jpg', quality=85):
    """
    批量转换文件夹中的所有图片
    """
    input_path = Path(input_dir)
    output_path = Path(output_dir)
    output_path.mkdir(parents=True, exist_ok=True)
    count = 0
    total_saved = 0
    for file_path in input_path.iterdir():
        if file_path.is_file() and file_path.suffix.lower() in SUPPORTED_EXTENSIONS:
            output_file = output_path / f"{file_path.stem}.{output_format}"
            img = Image.open(file_path)
            original_size = file_path.stat().st_size
            # 处理 RGBA → RGB
            if output_format in ('jpg', 'jpeg', 'bmp') and img.mode == 'RGBA':
                background = Image.new('RGB', img.size, (255, 255, 255))
                background.paste(img, mask=img.split()[3])
                img = background
            save_kwargs = {}
            if output_format in ('jpg', 'jpeg'):
                save_kwargs = {'quality': quality, 'optimize': True}
            elif output_format == 'webp':
                save_kwargs = {'quality': quality, 'method': 6}
            img.save(output_file, **save_kwargs)
            new_size = output_file.stat().st_size
            total_saved += original_size - new_size
            count += 1
    print(f"\n批量转换完成: {count} 张图片")
    print(f"节省空间: {total_saved / 1024 / 1024:.2f} MB")
# ==================== 方案 3：批量压缩（不改变格式） ====================
def batch_compress_images(input_dir, output_dir, quality=75, max_width=1920, max_height=1080):
    """
    批量压缩图片（保持原格式，降低质量和尺寸）
    """
    input_path = Path(input_dir)
    output_path = Path(output_dir)
    output_path.mkdir(parents=True, exist_ok=True)
    count = 0
    total_saved = 0
    for file_path in input_path.iterdir():
        if file_path.is_file() and file_path.suffix.lower() in {'.jpg', '.jpeg', '.png', '.webp'}:
            img = Image.open(file_path)
            # 缩小尺寸
            if max_width and max_height:
                img.thumbnail((max_width, max_height), Image.LANCZOS)
            save_kwargs = {}
            if file_path.suffix.lower() in ('.jpg', '.jpeg'):
                save_kwargs = {'quality': quality, 'optimize': True}
            output_file = output_path / file_path.name
            img.save(output_file, **save_kwargs)
            original_size = file_path.stat().st_size
            new_size = output_file.stat().st_size
            total_saved += original_size - new_size
            count += 1
    print(f"批量压缩完成: {count} 张图片")
    print(f"节省空间: {total_saved / 1024 / 1024:.2f} MB")
# ==================== 使用示例 ====================
if __name__ == "__main__":
    # 单个转换
    # convert_image("photo.png", output_format='jpg', quality=85)
    # 批量转 WebP（网页优化）
    batch_convert_folder("产品图片", "产品图片_WebP", output_format='webp', quality=80)
    # 批量压缩
    # batch_compress_images("原始照片", "压缩照片", quality=75, max_width=1920)

pip install imageio

import imageio

frames = imageio.mimread('animation.gif')
imageio.mimwrite('output.webp', frames, duration=0.1)