在VB.Net中保存图片时，如何将图片大小限制为图片框中的指定尺寸

如果有人能非常友好地告诉我如何在保存时将图片大小限制在指定的尺寸（例如150×200像素），我将非常高兴。如果不符合要求，则错误消息应指示所需的维度

但是，下面是将图片上载到图片框的代码

Private Sub btnUpload_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpload.Click
    Try
        OpenFileDialog1.ShowDialog()
        PictureBox1.Image = Image.FromFile(OpenFileDialog1.FileName)
        img = OpenFileDialog1.FileName.ToString
    Catch
    End Try
End Sub

If Image.FromFile(OpenFileDialog1.FileName).Size.Width > 150 Or Image.FromFile(OpenFileDialog1.FileName).Size.Height > 200 Then 
   lblPhotoErr.Text = "More than 150 x 200"
   bError = True
End If