iOS 图片的存储以及读取和删除

 NSArray *dirArray = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
            NSString *path = [dirArray firstObject];
            path = [path stringByAppendingPathComponent:[NSString stringWithFormat:@"IDCARD%zd",_selectIndex]];
            NSData *imageData = UIImageJPEGRepresentation(image, 1.0);
            [imageData writeToFile:path atomically:YES];

 NSArray *dirArray = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
        NSString *path = [dirArray firstObject];
        path = [path stringByAppendingPathComponent:[NSString stringWithFormat:@"IDCARD%zd",i]];
        if([[NSFileManager defaultManager] fileExistsAtPath:path]){
            NSData *picData = [NSData dataWithContentsOfFile:path];
            view.idCardImageView.image = [UIImage imageWithData:picData];
            }

 NSArray *dirArray = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
        NSString *path = [dirArray firstObject];
        path = [path stringByAppendingPathComponent:[NSString stringWithFormat:@"IDCARD%zd",i]];
        if([[NSFileManager defaultManager] fileExistsAtPath:path])//如果存在临时文件的配置文件
        {
            [[NSFileManager defaultManager]  removeItemAtPath:path error:nil];
        }