The solution ! 


Key Outlook 2013: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Options\Mail

Key Outlook 2016: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\Mail

Value type: REG_DWORD

Value name; Send Pictures With Document

Value: 1


Note: The value name contains spaces and capital letters; you must include these as well.