复制from PIL import Image
import io

# 打开图片
img = Image.open('input.jpg')

# 压缩为 JPEG，quality 范围 1-95，数值越低体积越小
buffer = io.BytesIO()
img.save(buffer, format='JPEG', quality=50, optimize=True)
compressed = buffer.getvalue()

print(f'原始大小: {img.fp.tell() if img.fp else "未知"} 字节')
print(f'压缩后大小: {len(compressed)} 字节')

# 保存到文件
with open('output.jpg', 'wb') as f:
    f.write(compressed)

复制package main

import (
	"image/jpeg"
	"os"
)

func main() {
	// 打开原始图片
	inFile, err := os.Open("input.jpg")
	if err != nil {
		panic(err)
	}
	defer inFile.Close()

	img, err := jpeg.Decode(inFile)
	if err != nil {
		panic(err)
	}

	// 创建输出文件
	outFile, err := os.Create("output.jpg")
	if err != nil {
		panic(err)
	}
	defer outFile.Close()

	// quality 参数 1-100，50 表示中等压缩
	err = jpeg.Encode(outFile, img, &jpeg.Options{Quality: 50})
	if err != nil {
		panic(err)
	}
}

复制// 浏览器端压缩（使用 Canvas API）
function compressImage(file, quality = 0.5) {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();
    reader.onload = (e) => {
      const img = new Image();
      img.onload = () => {
        const canvas = document.createElement('canvas');
        canvas.width = img.width;
        canvas.height = img.height;
        const ctx = canvas.getContext('2d');
        ctx.drawImage(img, 0, 0);
        // 输出为 JPEG，quality 0-1
        canvas.toBlob((blob) => {
          resolve(blob);
        }, 'image/jpeg', quality);
      };
      img.src = e.target.result;
    };
    reader.readAsDataURL(file);
  });
}

// 使用示例
// const fileInput = document.querySelector('input[type="file"]');
// fileInput.addEventListener('change', async (e) => {
//   const compressed = await compressImage(e.target.files[0], 0.5);
//   console.log('压缩后大小:', compressed.size, '字节');
// });