//类方法  图片 转换为二进制+(NSData *)Image_TransForm_Data:(UIImage *)image{    NSData *imageData = http://www.mamicode.com/UIImageJPEGRepresentation(image , 0.5);
    //几乎是按0.5图片大小就降到原来的一半 比如这里 24KB 降到11KB    return imageData;}//调用方法举例-(void)viewWillAppear:(BOOL)animated{    [self Read_ImageData];}- (void)viewDidLoad{     nav_View=[[NavView alloc]init];    [self.view addSubview: [nav_View NavView_Title:@"通告"]];    [super viewDidLoad];    [self Read_ImageData];}//以下方法 就是把一图片压缩成二进制 再转换成图片做显示 效果 不错-(void)Read_ImageData{    UIImageView *imageView1=[[UIImageView alloc]initWithFrame:CGRectMake(0, 80, 200, 200)];    imageView1.image=[UIImage imageNamed:@"cat_food.png"];    [self.view addSubview:imageView1];         UIImageView *imageView3=[[UIImageView alloc]initWithFrame:CGRectMake(0, 280, 200, 200)];    imageView3.image=[UIImage imageWithData:[Function Image_TransForm_Data:imageView1.image] ];    [self.view addSubview:imageView3];    NSData *data =http://www.mamicode.com/ [NSData dataWithData:[Function Image_TransForm_Data:imageView1.image ]];    [data writeToFile:[Function CreateTheFolder_From:Library_Cache FileHolderName:MyFolder FileName:@"pp111111.png"] atomically:YES];}