I understand they are textboxes, but I didn't know if you were intentionally giving IS_1 priority over IR_1.

In otherwords, if IS_1.Text = Today_Low then it overwrites any images set by the first If statement. This could be more efficiently re-written as:
VB Code:
  1. If IS_1.Text = Today_Low Then

  2.     Image1.Visible = True

  3.     Image2.Visible = False

  4. ElseIf IR_1.Text = Today_High Then

  5.     Image2.Visible = True

  6.     Image1.Visible = False

  7. End If