cocoa-touch - UIImageJPEGRepresentation が EXC BAD ACCESS をスローする

Question

画像と数値の2つの引数を受け取った関数があります。以下の関数は、「imgData = UIImageJPEGRepresentation(image, 1.0);」行で EXC BAD ACCESS をスローします。理由はわかりません:-(何かアイデアはありますか?

- (void)saveImages:(UIImage*)image row:(int)row {
  if (image != nil) {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString* path1 = [documentsDirectory stringByAppendingPathComponent: 
                      [NSString stringWithFormat:@"%i.JPEG", row]];
    NSString* path2 = [documentsDirectory stringByAppendingPathComponent: 
                      [NSString stringWithFormat:@"%is.JPEG", row]];

    NSData* imgData;
    imgData = UIImageJPEGRepresentation(image, 1.0);
    [imgData writeToFile:path1 atomically:YES];

    [self rotateIcon:image];
    image = [self imageWithImage:image];
    NSData* smalImgData = UIImageJPEGRepresentation(image, 1.0);
    [smalImgData writeToFile:path2 atomically:YES];
  }
}