gistfile1.txt

    UIImage *instaImage = [UIImage imageNamed:@"imagetoShare.png"];

    NSString* imagePath = [NSString stringWithFormat:@"%@/image.igo",[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
		NSUserDomainMask, YES) lastObject]];

    [[NSFileManager defaultManager] removeItemAtPath:imagePath error:nil];

    [UIImagePNGRepresentation(instaImage) writeToFile:imagePath atomically:YES];

    UIDocumentInteractionController *_docController = [UIDocumentInteractionController interactionControllerWithURL:
		[NSURL fileURLWithPath:imagePath]];

    _docController.UTI = @"com.instagram.exclusivegram";

    [_docController presentOpenInMenuFromRect:self.view.frame inView:self.view animated:YES];