I used below code in my projects to post the image it works fine.
if([SLComposeViewController instanceMethodForSelector:@selector(isAvailableForServiceType)] != nil)
{
if([SLComposeViewController isAvailableForServiceType:SLServiceTypeFacebook])
{
SLComposeViewController *controller = [SLComposeViewController composeViewControllerForServiceType:SLServiceTypeFacebook];
SLComposeViewControllerCompletionHandler myBlock = ^(SLComposeViewControllerResult result){
if (result == SLComposeViewControllerResultCancelled) {
NSLog(@"Cancelled");
} else
{
NSLog(@"Done");
}
[controller dismissViewControllerAnimated:YES completion:Nil];
};
controller.completionHandler =myBlock;
[controller setInitialText:@"Check out my Christmas Gift!"];
[controller addImage:@"gift.jpg"];
[self presentViewController:controller animated:YES completion:Nil];
}
You just try follow below tutorials