I'm with you Chris. I have a few photos on a-d and a.net which were taken 40 years or so ago. I've had requests for permission to use by someone who updates wikipedia foreign language versions, and an Australian aviation historian who has a website documenting aircraft registered in Australia prior to 1970. I have given both approval.
I was given a formal copyright release to sign by Wikipedia, which requires anyone using the image to attach a legal document almost a page long, which discourages unorthorised use. My images now appear in Russian, Italian, Czeck, Korean and Turkish editions of Wikipedia.
If an owner requests a photo of his aircraft, I will supply a hi-res version by email. If he requests a printed copy, I ask him to pay printing and postage.
I also supplied a photo to Australia's ATSB for inclusion in an accident report.
All users attached credits to photos used.