If you are using SLComposeViewController
user only post a message to facebook. Before using SLComposeViewController
you need to add Social FrameWork.
if([SLComposeViewController isAvailableForServiceType:SLServiceTypeFacebook])
{
SLComposeViewController *controller = [SLComposeViewController composeViewControllerForServiceType:SLServiceTypeFacebook];
[controller setInitialText:@"Using Facebook to share your Images"];
[controller addImage:PresentImg];
[self presentViewController:controller animated:YES completion:Nil];
}