How to convert an attached image to Base64 format.

Public Function EncodeFile(strPicPath As String) As String
    Const adTypeBinary = 1          ' Binary file is encoded

    ' Variables for encoding
    Dim objXML
    Dim objDocElem

    ' Variable for reading binary picture
    Dim objStream

    ' Open data stream from picture
    Set objStream = CreateObject("ADODB.Stream")
    objStream.Type = adTypeBinary
    objStream.Open
    objStream.LoadFromFile (strPicPath)

    ' Create XML Document object and root node
    ' that will contain the data
    Set objXML = CreateObject("MSXml2.DOMDocument")
    Set objDocElem = objXML.createElement("Base64Data")
    objDocElem.dataType = "bin.base64"

    ' Set binary value
    objDocElem.nodeTypedValue = objStream.Read()

    ' Get base64 value
    EncodeFile = objDocElem.Text

    ' Clean all
    Set objXML = Nothing
    Set objDocElem = Nothing
    Set objStream = Nothing

End Function