Scrolling

I have a form with an Image Allocation Plan

Option Compare Database
Option Explicit

    Dim AllocationPlanWidth As Long
    Dim AllocationPlanHeight As Long

Private Sub AllocationPlan_Click()

    If AllocationPlan.Width < Me.Width Then         ' Normal size
        SpaceTypeID.SetFocus
        SpaceAllocationSub.Visible = False
        LabelClickPicture.Visible = False
        AllocationPlanWidth = AllocationPlan.Width
        AllocationPlanHeight = AllocationPlan.Height
        AllocationPlan.Width = Me.Width                 ' Expand
        AllocationPlan.Height = Me.Section(0).Height
        Me.ScrollBars = 3
    Else
        SpaceAllocationSub.Visible = True
        LabelClickPicture.Visible = True
        AllocationPlan.Width = AllocationPlanWidth      ' Restore to 
original
        AllocationPlan.Height = AllocationPlanHeight
        Me.ScrollBars = 0
    End If

End Sub

As you see from the above code, on clicking the image it enlarges, and on 
clicking again it restores it to the original size. I also have to hide a 
subform SpaceAllocationSub to show the larger image.

Interestingly ( and probably fortuitously) each time you do a pair of
clicks 
the image gets a bit bigger. I suspect that the form size is changing.

Problem is that with the bigger image I have to make the form's scrollbars

visible. If you scroll down to the bottom left of the form, then click the

image to restore it to the smaller size, I loose the top of the form.
How can I ensure that I scroll to the Top Left before going to the smaller

image?

Phil