How to add a pic after the signature of an email

Hello I have created a script to add picture at the end of an email after my signature, but actually the picture is added inside my signature and not after it.

Can anyone could point out a solution?

--add signature
tell application "Mail"
	set the message signature of newMessage to signature "KR Promo"
end tell

--add optional picture
set the_file to choose file with prompt "Choose the picture file to attach:"
tell application "Mail"
	tell newMessage to make new attachment with properties {file name:the_file}
end tell

Perhaps all you need to do is edit your signature in Mail->Preferences->Signatures and add a return or 2 after it. Or possible include a space or character in case it trims it.

You do realize that you can drag a picture into your signature . . .