public void Add(
	byte[] data,
	string targetFilename,
	string contentID,
	string contentType,
	HeaderCollection customHeaders,
	NewAttachmentOptions options,
	MailTransferEncoding mailEnc
)

Public Sub Add ( 
	data As Byte(),
	targetFilename As String,
	contentID As String,
	contentType As String,
	customHeaders As HeaderCollection,
	options As NewAttachmentOptions,
	mailEnc As MailTransferEncoding
)

// To use the code below, import these namespaces at the top of your code.
using System.IO;
using MailBee;
using MailBee.Mime;

// Create new data buffer as binary array.
byte[] fileData = null;

// Open a file for reading.
using (FileStream fs = new FileStream(@"C:\Temp\1.gif", FileMode.Open))
{
    // Set the size of the buffer.
    fileData = new byte[fs.Length];

    // Create new BinaryReader object.
    BinaryReader br = new BinaryReader(fs);

    // Read binary data from file to buffer.
    br.Read(fileData, 0, fileData.Length);
}

// Create a new MailMessage object.
MailMessage msg = new MailMessage();

// Add an attachment to the message.
msg.Attachments.Add(fileData, "my.gif", "<12s4a8a8778c$5664i1b1$ir671781@tlffmdqjobxj>", "image/gif", null, NewAttachmentOptions.None, MailTransferEncoding.Base64);

' To use the code below, import these namespaces at the top of your code.
Imports System.IO
Imports MailBee
Imports MailBee.Mime

' Create new data buffer as binary array.
Dim fileData As Byte() = Nothing

' Open file for read.
Dim fs As FileStream
Try
    fs = New FileStream("C:\Temp\1.gif", System.IO.FileMode.Open)

    ' Set the size of the buffer.
    ReDim fileData(fs.Length)

    ' Create new BinaryReader object.
    Dim br As New BinaryReader(fs)

    ' Read binary data from file to buffer.
    br.Read(fileData, 0, fileData.Length)
Finally
    If Not fs Is Nothing Then fs.Close()
End Try

' Create new MailMessage object.
Dim msg As New MailMessage

' Add an attachment to the message.
msg.Attachments.Add(fileData, "my.gif", "<12s4a8a8778c$5664i1b1$ir671781@tlffmdqjobxj>", "image/gif", Nothing, NewAttachmentOptions.None, MailTransferEncoding.Base64)