Is it OK to run GC.Collect in a background thread?

Following this SO answer, I'm doing:

ThreadPool.QueueUserWorkItem(
    delegate
    {
        GC.Collect();
        GC.WaitForPendingFinalizers();
        GC.Collect();
    });

My goal is to do a garbage collection run after I close a large WinForms form with lots of images/PictureBox controls to ensure I have no images in memory anymore. (I do believe I follow the instructions of Jon Skeet).

I'm doing it in a background thread in order to try to have my UI responsive.

My question:

Does it bring me any benefits to do the garbage collection in a background thread? Or does it actually make my application slower/hang longer?