从入门到实战详解Python压缩图片的完整方法

from PIL import Image

def compress_image(input_path, output_path, quality=85):
    """
    quality: 1-100，越小文件越小，画质越差
    推荐值：70-85 之间性价比最高
    """
    img = Image.open(input_path)
    
    # JPEG 不支持透明通道，需要转换模式
    if img.mode in ('RGBA', 'P'):
        img = img.convert('RGB')
    
    img.save(output_path, 'JPEG', optimize=True, quality=quality)
    
    original_size = os.path.getsize(input_path) / 1024
    new_size = os.path.getsize(output_path) / 1024
    print(f"原大小: {original_size:.1f}KB → 压缩后: {new_size:.1f}KB，节省 {100 - new_size/original_size*100:.1f}%")

compress_image("photo.jpg", "photo_compressed.jpg", quality=80)

def resize_image(input_path, output_path, max_width=1200):
    img = Image.open(input_path)
    
    w, h = img.size
    if w > max_width:
        ratio = max_width / w
        new_size = (max_width, int(h * ratio))
        img = img.resize(new_size, Image.LANCZOS)  # LANCZOS 是高质量缩放算法
    
    img.save(output_path, 'JPEG', optimize=True, quality=85)

import os
from PIL import Image

def batch_compress(input_dir, output_dir, quality=80):
    os.makedirs(output_dir, exist_ok=True)
    
    for filename in os.listdir(input_dir):
        if filename.lower().endswith(('.jpg', '.jpeg', '.png', '.webp')):
            input_path = os.path.join(input_dir, filename)
            output_path = os.path.join(output_dir, filename)
            
            img = Image.open(input_path)
            if img.mode in ('RGBA', 'P'):
                img = img.convert('RGB')
            img.save(output_path, 'JPEG', optimize=True, quality=quality)
            print(f"✅ {filename}")

batch_compress("./photos", "./photos_compressed", quality=75)

import cv2

def compress_with_cv2(input_path, output_path, quality=80):
    img = cv2.imread(input_path)
    # quality 参数范围 0-100
    cv2.imwrite(output_path, img, [cv2.IMWRITE_JPEG_QUALITY, quality])

import tinify

tinify.key = "你的API_KEY"
source = tinify.from_file("photo.jpg")
source.to_file("photo_tiny.jpg")

import os
from PIL import Image

def smart_compress(input_path, output_path, max_width=1920, quality=80):
    img = Image.open(input_path)
    
    # 1. 转换模式
    if img.mode in ('RGBA', 'P'):
        img = img.convert('RGB')
    
    # 2. 缩小尺寸
    w, h = img.size
    if w > max_width:
        ratio = max_width / w
        img = img.resize((max_width, int(h * ratio)), Image.LANCZOS)
    
    # 3. 压缩保存
    img.save(output_path, 'JPEG', optimize=True, quality=quality)
    
    original = os.path.getsize(input_path) / 1024
    compressed = os.path.getsize(output_path) / 1024
    print(f"{os.path.basename(input_path)}: {original:.0f}KB → {compressed:.0f}KB")

# 使用
smart_compress("large_photo.jpg", "small_photo.jpg")