Public Class Form1
    Dim graph As Graphics
    Dim g, g1 As System.Drawing.Graphics
    Dim img As New Bitmap(144, 16)
    Dim brush As New Drawing.SolidBrush(Color.Black)
    Private Sub TextBox1_TextChanged(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.TextChanged
        g1 = Graphics.FromImage(img)
        PictureBox1.Image = img
        ' to clear the bitmap
        g1.Clear(Color.White)
        'for drawsting function
        g1.SmoothingMode = Drawing2D.SmoothingMode.HighQuality
        g1.TextRenderingHint = Drawing.Text.TextRenderingHint.SingleBitPerPixelGridFit
        g1.CompositingQuality = Drawing2D.CompositingQuality.HighQuality
        'to draw string
        g1.DrawString(TextBox1.Text, TextBox1.Font, Brushes.Black, 0, 0)
        PictureBox1.SizeMode = PictureBoxSizeMode.Normal
        PictureBox1.Refresh()
    End Sub
End Class

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        Dim file As String = String.Format("{0}\{1}.bmp", Application.StartupPath, e.KeyChar.ToString)
 
        If System.IO.File.Exists(file) Then
 
            PictureBox1.ImageLocation = file
 
        Else
 
            PictureBox1.ImageLocation = String.Empty
 
        End If
    End Sub