1. 在上传图片前，先检查图片大小并裁剪到指定大小：

const file = document.querySelector('#image').files[0];
const MAX_SIZE = 1024 * 1024; // 1MB
if (file.size > MAX_SIZE) {
  const image = await loadImage(file);
  const resizedImage = await resizeImage(image, { width: 800, height: 600 });
  const croppedImage = await cropImage(resizedImage, { width: 800, height: 600 });
  const blob = await imageToBlob(croppedImage, 'image/jpeg', 0.8);
  const newFile = new File([blob], 'croppedImage.jpg', { type: blob.type });
  // use newFile for S3 upload
} else {
  // use file for S3 upload
}

2. 在上传图片时，设置S3对象存储桶的CORS规则，允许跨域访问：

[
  {
    "AllowedHeaders": [
      "*"
    ],
    "AllowedMethods": [
      "GET",
      "PUT",
      "POST",
      "DELETE"
    ],
    "AllowedOrigins": [
      "*"
    ],
    "ExposeHeaders": []
  }
]

3. 在上传图片时，设置S3对象存储桶的ACL权限为public-read：

const uploadParams = {
  Bucket: 'myBucket',
  Key: 'myImage.jpg',
  Body: fileData,
  ACL: 'public-read'
};
const result = await s3Client.upload(uploadParams).promise();