Or, mod my slightly and get rid of graphical property.....
Code:
Option Explicit
Dim gCmd1Clicked As Boolean
Dim gCmd2Clicked As Boolean

Private Sub Command1_Click()
If gCmd1Clicked = False Then
    gCmd1Clicked = True
    gCmd2Clicked = False
    Command1.Enabled = False
    Command2.Enabled = True
'    Command1.Picture = LoadPicture(App.Path & "\downbtn.jpg")
'    Command2.Picture = LoadPicture(App.Path & "\upbtn.jpg")
Else
    gCmd1Clicked = False
'    Command1.Enabled = True
End If
End Sub

Private Sub Command2_Click()
If gCmd2Clicked = False Then
    gCmd2Clicked = True
    gCmd1Clicked = False
    Command2.Enabled = False
    Command1.Enabled = True
'    Command2.Picture = LoadPicture(App.Path & "\downbtn.jpg")
'    Command1.Picture = LoadPicture(App.Path & "\upbtn.jpg")
Else
    gCmd2Clicked = False
'    Command2.Enabled = True
End If
End Sub