Private Shared Function ConvertHexToBytes(hex As String) As Byte()
        Dim bytes As Byte() = New Byte(hex.Length / 2 - 1) {}
        For i As Integer = 0 To hex.Length - 1 Step 2
            bytes(i / 2) = Convert.ToByte(hex.Substring(i, 2), 16)
        Next
        Return bytes
    End Function
 
 
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles _
      Button1.Click
        Try
            TextBox1.Text = "35313230303B303B313B31373131313....77"
 
            Dim image_stream As New MemoryStream(StrToByteArray(TextBox1.Text))
            PictureBox1.Image = Image.FromStream(image_stream)