> pragma mark 从用户相册获取活动图片
- (void)pickImageFromAlbum
{
    imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.delegate =self;
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    imagePicker.allowsEditing =YES;
  [self presentModalViewController:imagePicker animated:YES];
}

> pragma mark 从摄像头获取活动图片

- (void)pickImageFromCamera
{
    imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.delegate =self;
    imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
    imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    imagePicker.allowsEditing =YES;
    
    [self presentModalViewController:imagePicker animated:YES];
}
//打开相机
- (IBAction)touch_photo:(id)sender {
    // for iphone
    UIImagePickerController *pickerImage = [[UIImagePickerController alloc] init];
   if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        pickerImage.sourceType = UIImagePickerControllerSourceTypeCamera;
        pickerImage.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:pickerImage.sourceType];
        
    }
    pickerImage.delegate =self;
    pickerImage.allowsEditing =YES;//自定义照片样式
    [self presentViewController:pickerImage animated:YES completion:nil];
}

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info
{
    //初始化imageNew为从相机中获得的--
    UIImage *imageNew = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
    //设置image的尺寸
    CGSize imagesize = imageNew.size;
    imagesize.height =626;
    imagesize.width =413;
  

>   //对图片大小进行压缩--

    imageNew = [self imageWithImage:imageNew scaledToSize:imagesize];
    NSData *imageData = UIImageJPEGRepresentation(imageNew,0.00001);
   if(m_selectImage==nil)
    {
        m_selectImage = [UIImage imageWithData:imageData];
        NSLog(@"m_selectImage:%@",m_selectImage);
        [self.TakePhotoBtn setImage:m_selectImage forState:UIControlStateNormal];
        [picker dismissModalViewControllerAnimated:YES];
       return ;
    }
    [picker release];
}

> //对图片尺寸进行压缩--

-(UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize
{
    // Create a graphics image context
    UIGraphicsBeginImageContext(newSize);
    
    // Tell the old image to draw in this new context, with the desired
    // new size
    [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
    
    // Get the new image from the context
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // End the context
    UIGraphicsEndImageContext();
    
    // Return the new image.
   return newImage;
}

图片保存到本地document里面--以及图片格式的转换
IOS开发之保存图片到Documents目录及PNG，JPEG格式相互转换
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary*)info {
    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
    if ([mediaType isEqualToString:@"public.image"]){
        image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
        NSData *data;
        if (UIImagePNGRepresentation(image) == nil) {
            data = UIImageJPEGRepresentation(image, 1);
        } else {
            data = UIImagePNGRepresentation(image);
        }
        
        NSFileManager *fileManager = [NSFileManager defaultManager];
        NSString *filePath = [NSString stringWithString:[self getPath:@"image1"]];         //将图片存储到本地documents
         [fileManager createDirectoryAtPath:filePath withIntermediateDirectories:YES attributes:nil error:nil];
         [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.png"] contents:dataattributes:nil];
        
        UIImage *editedImage = [[UIImage alloc] init];
        editedImage = image;
        CGRect rect = CGRectMake(0, 0, 64, 96);
        UIGraphicsBeginImageContext(rect.size);
        [editedImage drawInRect:rect];
        editedImage = UIGraphicsGetImageFromCurrentImageContext();
        
        UIButton *imageButton = [UIButton buttonWithType:UIButtonTypeCustom];
        imageButton.frame = CGRectMake(10, 10, 64, 96);
        [imageButton setImage:editedImage forState:UIControlStateNormal];
        [self.view addSubview:imageButton];
        [imageButton addTarget:self action:@selector(imageAction:)forControlEvents:UIControlEventTouchUpInside];
        [ipc dismissModalViewControllerAnimated:YES];
    } else {
        NSLog(@"MEdia");
    }
    
//上面的代码是当从相册里面选取图片之后保存到本地程序沙盒，在上面我们得到的图片中不能够得到图片名字，
//以及不清楚图片格式，所以这个时候我们需要将其转换成NSdata二进制存储，
 image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
NSData *data;
        if (UIImagePNGRepresentation(image) == nil) {
            data = UIImageJPEGRepresentation(image, 1);
        } else {
            data = UIImagePNGRepresentation(image);
        }
//UIImagePNGRepresentation转换PNG格式的图片为二进制，如果图片的格式为JPEG则返回nil；
 [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.png"] contents:data attributes:nil];    
 //将图片保存为PNG格式
 [fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.jpg"] contents:data attributes:nil];   
//将图片保存为JPEG格式
//我们也可以写成下面的格式存储图片
NSString *pngImage = [filePath stringByAppendingPathComponent:@"Documents/image.png"];
NSString *jpgImage = [filePath stringByAppendingPathComponent:@"Documents/image.jpg"];
[data writeToFile:pngImage atomically:YES];
[data writeToFile:jpgImage atomically:YES];