Turn a Base64 encoded string into a .png image

this is the part of the xml that has the image.
<Image ImageFormat="PNG" dt:dt="bin.base64" xmlns:dt="urn:schemas-microsoft-com:datatypes">iVBORw0KGgoAAAANSUhEUgAAAp0AAAIvAQMAAAAMGfIDA....AAAAAElFTkSuQmCC</Image>
 
I'm using the following VBA:
Const sBASE_64_CHARACTERS  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
 
Function fGetWebPost(strSourceURL As String, strRequest As String)
Dim xmlServerHttp As Object, co As Long, s As String
Set xmlServerHttp = CreateObject("MSXML2.ServerXMLHTTP.4.0")
With xmlServerHttp
    .Open "POST", strSourceURL, False
    '.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
    .send (strRequest)
    s = .responseText
End With
fGetWebPost = s
 
 
Open "c:\test.png" For Output As #1
Print #1, Base64decode(Mid(s, 1312, 11798))
Close #1
 
Set xmlServerHttp = Nothing
End Function
'**************************************
    ' Name: Base 64 Encode / Decode
    ' Description:Base 64 encodeing is used
    '     to convert binary files to a "safe" form
    '     at for transporting files through smtp (
    '     email) and other protocols. It is also u
    '     sed for basic authentication. With this
    '     code, you can decode the current UserNam
    '     e/Password who is visiting a protected p
    '     age on your site by requesting one of th
    '     e serverVariables.
    ' By: Lewis E. Moten III
    '
    ' Inputs:These two algorithims are expec
    '     ting a string that is to be encoded or d
    '     ecoded.
    '
    ' Returns:Returns a string that was enco
    '     ded or decoded.
    '
    ' Side Effects:The string returned from
    '     encoding with Base64 is not delimited by
    '     cariadge returns. Some formats that I ha
    '     ve seen in the past, such as email - may
    '     continue to the next line after the 80th
    '     character.
    'Also, these functions work With Strings. (Not binary data). When working with binary data, some changes may need To come into place.
    '
    'This code is copyrighted and has    ' limited warranties.Please see http://w
    '     ww.Planet-Source-Code.com/vb/scripts/Sho
    '     wCode.asp?txtCodeId=6268&lngWId=4    'for details.    '**************************************
    
    ' --------------------------------------
    '     ---------------------------------------
    Function Base64decode(ByVal asContents)
        Dim lsResult
        Dim lnPosition
        Dim lsGroup64, lsGroupBinary
        Dim Char1, Char2, Char3, Char4
        Dim Byte1, Byte2, Byte3
        If Len(asContents) Mod 4 > 0 Then asContents = asContents & String(4 - (Len(asContents) Mod 4), " ")
        lsResult = ""
        
        For lnPosition = 1 To Len(asContents) Step 4
            lsGroupBinary = ""
            lsGroup64 = Mid(asContents, lnPosition, 4)
            Char1 = InStr(sBASE_64_CHARACTERS, Mid(lsGroup64, 1, 1)) - 1
            Char2 = InStr(sBASE_64_CHARACTERS, Mid(lsGroup64, 2, 1)) - 1
            Char3 = InStr(sBASE_64_CHARACTERS, Mid(lsGroup64, 3, 1)) - 1
            Char4 = InStr(sBASE_64_CHARACTERS, Mid(lsGroup64, 4, 1)) - 1
            Byte1 = Chr(((Char2 And 48) \ 16) Or (Char1 * 4) And &HFF)
            Byte2 = lsGroupBinary & Chr(((Char3 And 60) \ 4) Or (Char2 * 16) And &HFF)
            Byte3 = Chr((((Char3 And 3) * 64) And &HFF) Or (Char4 And 63))
            lsGroupBinary = Byte1 & Byte2 & Byte3
            
            lsResult = lsResult + lsGroupBinary
        Next
        Base64decode = lsResult
    End Function