iOS 对图片进行压缩

- (UIImage *)compressImage:(UIImage *)image toMaxFileSize:(NSInteger)maxFileSize {
    CGFloat compression = 0.9f;
    CGFloat maxCompression = 0.1f;
    NSData *imageData = UIImageJPEGRepresentation(image, compression);
    while ([imageData length] > maxFileSize && compression > maxCompression) {
        compression -= 0.1;
        imageData = UIImageJPEGRepresentation(image, compression);
    }
    
    UIImage *compressedImage = [UIImage imageWithData:imageData];
    return compressedImage;
}