Many thx for the update Dimitry !
Thx for this advice, I can see this works. However I have used freemind for years and have not needed to do this until very recently. I have hundreds of mind maps with images. Is there some setting I can apply that can do this for me - I am assuming that something has changed for this new behaviour - Is there something I can do to counter it that does not involve editing every image I have in all my mind maps?