Public Function ExtractBase64String(text As String) As String
    Dim startStr As String
    Dim endStr As String
    Dim startPos As Long
    Dim endPos As Long

    ' Definiraj pocetni i zavrsni parametar
    startStr = """invoiceImagePngBase64"":"""
    endStr = """,""invoiceNumber"""

    ' Nadji pozicije pocetka i kraja stringa
    startPos = InStr(text, startStr)
    If startPos = 0 Then
        ExtractBase64String = "Start string not found"
        Exit Function
    End If
    startPos = startPos + Len(startStr) ' Pomakni poziciju na kraj start stringa

    endPos = InStr(startPos, text, endStr)
    If endPos = 0 Then
        ExtractBase64String = "End string not found"
        Exit Function
    End If

    ' Izvuci substring izmedju pocetka i kraja
    ExtractBase64String = "data:image/gif;base64," & Mid(text, startPos, endPos - startPos)
End Function