X-WSSE: UsernameToken Username="***", PasswordDigest="XXX", Nonce="XXX", Created="2008-12-01T12:00:00"

Protected Shared Function CreateWsseHeaderValue(ByVal userName As String, ByVal password As String) As String
     Dim sha1 = New System.Security.Cryptography.SHA1CryptoServiceProvider
     Dim created = Now.ToString("s") ' Created
     Dim nonce = Guid.NewGuid.ToString ' Nonce
     Dim passwordDigest = Convert.ToBase64String( _
         sha1.ComputeHash(System.Text.Encoding.ASCII.GetBytes(nonce & created & password))) ' PasswordDigest

     Return String.Format("UsernameToken Username=""{0}"", PasswordDigest=""{1}"", Nonce=""{2}"", Created=""{3}""", _
                          userName, passwordDigest, Convert.ToBase64String(System.Text.Encoding.ASCII.GetBytes(nonce)), created)
 End Function

<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://purl.org/atom/ns#">
  <link type="application/x.atom+xml" rel="service.post"
        href="http://f.hatena.ne.jp/atom/post" title="sample">
  <link type="application/x.atom+xml" rel="service.feed"
        href="http://f.hatena.ne.jp/atom/feed" title="sample">
</feed>

Imports <xmlns="http://purl.org/atom/ns#">

Protected Shared Function GetPostUri(ByVal userName As String, ByVal password As String, ByRef title As String) As String
    ' リクエストの作成
    Dim request = DirectCast(WebRequest.Create("http://f.hatena.ne.jp/atom"), HttpWebRequest)
    With request
        .Method = "GET"

        ' WSSE認証用
        .Headers.Add(HttpRequestHeader.Authorization, "WSSE profile=""UsernameToken""")
        .Headers.Add("X-WSSE", CreateWsseHeaderValue(userName, password))

        .Accept = "application/x.atom+xml, application/xml, text/xml, */*"
        .ServicePoint.Expect100Continue = False
    End With

    ' レスポンスの取得
    Dim document As XDocument
    Using response = DirectCast(request.GetResponse, HttpWebResponse), _
          reader = New System.IO.StreamReader(response.GetResponseStream, System.Text.Encoding.UTF8)
        document = XDocument.Load(reader)
    End Using

    ' <link rel="service.post">要素の取得
    Dim elements = From e In document.<feed>.<link> Where e.@rel = "service.post"

    title = elements.First.@title ' title
    Return elements.First.@href ' PostUri
End Function

<entry xmlns="http://purl.org/atom/ns#">
    <title>[写真のタイトル]</title>
    <content mode="base64" type="[Content-Type]">[画像データをBase64エンコードしたもの]</content>
    <hatena:generator xmlns:hatena="http://www.hatena.ne.jp/info/xmlns#" url="example.jp" version="1.0">[アップロードツール名]</hatena:generator>
    <dc:subject xmlns:dc="http://purl.org/dc/elements/1.1/">[フォルダ名]</dc:subject>
</entry>

Imports <xmlns="http://purl.org/atom/ns#">
Imports <xmlns:hatena="http://www.hatena.ne.jp/info/xmlns#">
Imports <xmlns:dc="http://purl.org/dc/elements/1.1/">

Protected Shared Sub PostPhoto(ByVal userName As String, ByVal password As String, _
                                  ByVal postUri As String, ByVal photoPath As String)
    ' リクエストの作成
    Dim request = DirectCast(WebRequest.Create(postUri), HttpWebRequest)
    With request
        .Method = "POST"

        ' WSSE認証用
        .Headers.Add(HttpRequestHeader.Authorization, "WSSE profile=""UsernameToken""")
        .Headers.Add("X-WSSE", CreateWsseHeaderValue(userName, password))

        .ContentType = "application/x.atom+xml"
        .Accept = "application/x.atom+xml, application/xml, text/xml, */*"
        .ServicePoint.Expect100Continue = False
    End With

    ' 写真をバイト配列として読み込み
    Dim photoBuffer = New Byte() {}
    Using stream = New System.IO.FileStream(photoPath, IO.FileMode.Open, IO.FileAccess.Read), _
          reader = New System.IO.BinaryReader(stream)
        If stream.Length <= Integer.MaxValue Then
            photoBuffer = reader.ReadBytes(CInt(stream.Length))
        End If
    End Using

    ' <entry>要素
    Dim entry = <entry>
                    <title>Sample</title>
                    <content mode="base64" type="image/jpeg"><%= Convert.ToBase64String(photoBuffer) %></content>
                    <hatena:generator url="http://gihyo.jp/dev/serial/01/wl-sdk/" version="1.0">gihyo.jp sample tool</hatena:generator>
                    <dc:subject>Sample</dc:subject>
                </entry>

    ' <entry>要素をバイト配列へ変換
    Dim entryBuffer = System.Text.Encoding.UTF8.GetBytes(entry.ToString)
    request.ContentLength = entryBuffer.Length

    ' POSTデータ書き込み
    Using stream = request.GetRequestStream
        stream.Write(entryBuffer, 0, entryBuffer.Length)
    End Using

    ' レスポンス取得
    Dim document As XDocument
    Using response = DirectCast(request.GetResponse, HttpWebResponse), _
          reader = New System.IO.StreamReader(response.GetResponseStream, System.Text.Encoding.UTF8)
        document = XDocument.Load(reader)
    End Using
End Sub

Dim userName = "ユーザー名"
Dim password = "パスワード"
Dim title = ""

Dim postUri = GetPostUri(userName, password, title)
PostPhoto(userName, password, postUri, "C:\Users\UserName\Pictures\Sample.jpg")