Imports System.IO
Imports System.Drawing.Imaging
Public Class MainForm
    Dim encodeType As ImageFormat = ImageFormat.Jpeg
    Dim decodingString As String = String.Empty

    Private Sub MainForm_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub btnOpen_Click(sender As System.Object, e As System.EventArgs) Handles btnOpen.Click
        Dim newOpenFileDial As New OpenFileDialog()
        newOpenFileDial.Filter = "Images(*.jpg;.*png;*.gif;*.bmp)|*.jpg;.*png;*.gif;*.bmp"
        If newOpenFileDial.ShowDialog() = Windows.Forms.DialogResult.OK Then
            txtPath.Text = newOpenFileDial.FileName
            pbPreview.ImageLocation = txtPath.Text
        End If
    End Sub

    Private Sub btnImagetoBase64_Click(sender As System.Object, e As System.EventArgs) Handles btnImagetoBase64.Click
        txtSourceCode.Clear()
        Dim encodingTypeString As String = String.Empty
        If pbPreview.ImageLocation.ToLower.EndsWith(".jpg") Then
            encodeType = ImageFormat.Jpeg
            encodingTypeString = "data:image/jpeg;base64,"
        ElseIf pbPreview.ImageLocation.ToLower.EndsWith(".png") Then
            encodeType = ImageFormat.Png
            encodingTypeString = "data:image/png;base64,"
        ElseIf pbPreview.ImageLocation.ToLower.EndsWith(".gif") Then
            encodeType = ImageFormat.Gif
            encodingTypeString = "data:image/gif;base64,"
        ElseIf pbPreview.ImageLocation.ToLower.EndsWith(".bmp") Then
            encodeType = ImageFormat.Bmp
            encodingTypeString = "data:image/bmp;base64,"
        End If
        decodingString = encodingTypeString
        txtSourceCode.Text = encodingTypeString & ImageToBase64(pbPreview.Image, encodeType)
        pbPreview.Image = Nothing
    End Sub

    Public Function ImageToBase64(ByVal image As Image, ByVal format As ImageFormat) As String
        Using ms As New MemoryStream()
            image.Save(ms, format)
            Dim imageBytes As Byte() = ms.ToArray()
            Dim base64String As String = Convert.ToBase64String(imageBytes)
            Return base64String
        End Using
    End Function

    Private Sub btnBase64ToImage_Click(sender As System.Object, e As System.EventArgs) Handles btnBase64ToImage.Click
        txtSourceCode.Text = txtSourceCode.Text.Replace(decodingString, "")
        pbPreview.Image = Base64ToImage(txtSourceCode.Text)
    End Sub

    Public Function Base64ToImage(ByVal base64Code As String) As Image
        Dim imageBytes As Byte() = Convert.FromBase64String(base64Code)
        Dim ms As New MemoryStream(imageBytes, 0, imageBytes.Length)
        Dim tmpImage As Image = Image.FromStream(ms, True)
        Return tmpImage
    End Function

End Class