Mira intenté con este código y funciona, tarda un poco en cargar la imagen cuidado.
Código Visual Basic:
Ver originalDim ruta1, ruta2 As String
Dim eruta As Integer
Private Sub Form_Load()
ruta1 = "d:\Pimage1.jpg"
Image1.Picture = LoadPicture(ruta1)
eruta = 1
Image1.Enabled = True
End Sub
Private Sub Image1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
ruta1 = "d:\Pimage1.jpg"
ruta2 = "d:\Pimage2.jpg"
If eruta = 1 Then
eruta = 2
Image1.Picture = LoadPicture(ruta2)
ElseIf eruta = 2 Then
eruta = 1
Image1.Picture = LoadPicture(ruta1)
End If
End Sub