[RESOLVED] Garbage collecting images

[kebo]

Hey all,
Curiosity runs wild.

Suppose I have this code...

Do
            Static count As Integer = 0
            Me.PictureBox1.Image = New Bitmap(5000, 5000)
            count += 1
            Debug.Print(count)
            'breathe
            Threading.Thread.Sleep(10000)
        Loop

When I run this and watch memory consumption in the task manager, memory for the app continuously increases until I finally get an ArgumentException from System.Drawing.dll after 14 iterations.

If however I add a GC.Collect to the code, memory stays in check and it will continue to run...

Do
            Static count As Integer = 0
            Me.PictureBox1.Image = New Bitmap(5000, 5000)
            GC.Collect()' <---- Adding this allows the loop to run indefinitely
            count += 1
            Debug.Print(count)
            'breathe
            Threading.Thread.Sleep(10000)
        Loop

It was my understanding the the CLR will collect the garbage as needed, so what gives? Why do I need to manually collect garbage for this to work?