' create sub for making upload post
private sub upload_file()
  dim strPOST as string, Header as string Boundary as string, uagent as string
  dim Idboundary as string   ' id boundary for the site, it may different
  
  uagent = "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.12) Gecko/20050915 Firefox/1.0.7"
  INETPOST.host = "www.somesite.com"
  Idboundary = "9876543210123"    ' you can generate this number
  Boundary = String(27, "-") & Idboundary     ' mutipart post need "-" sign
  
  Header = uagent & vbCrLf & "Content-Type: multipart/form-data; " & "boundary=" & Boundary
  
  strPOST = "--" & Boundary & vbCrLf & _
  "Content-Disposition: form-data; name=""myfile""" & vbCrLf & vbCrLf & _
  """ & EncodeBin & """ & vbCrLf & _
"--" & Boundary & vbCrLf & _
"Content-Disposition: form-data; name=""upload""" & vbCrLf & vbCrLf & _
"Upload File" & vbCrLf & _
"--" & Boundary & "--" & vbCrLf

INETPOST.Execute "http://www.somesite.com/upload.php", "POST", strPOST, Header

  ' Wait untill it finished
  Do Until BekasNET.StillExecuting = False: DoEvents: Loop
end sub

' function to encode binary file
Function EncodeBin(SourceFile As String)
Dim buf As String, File1 As Integer

File1 = FreeFile

Open SourceFile For Binary Access Read As #File1
  ' make buffer to storing file's content
  buf = Space(LOF(File1))
  Get #File1, , buf
Close #File1

EncodeBin = buf

End Function