VBA code working with drop list with words instead of numbers

I have this code and it is working, but the drop list that I have in A1 have the values 1,2 and I want that works with the values "RIO","MAR".

Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)


If Not Intersect(Target, Range("A1")) Is Nothing Then
If IsNumeric(Target.Value) Then

If Target.Value = 1 Then

ActiveSheet.Shapes.Range(Array("Image2")).Visible = msoFalse
ActiveSheet.Shapes.Range(Array("Image1")).Visible = msoTrue

Else

ActiveSheet.Shapes.Range(Array("Image2")).Visible = msoTrue
ActiveSheet.Shapes.Range(Array("Image1")).Visible = msoFalse
End If
End If
End If

End Sub

Thank you for your help