Usually it is assumed that everything is free on the internet.
If you need a specific photograph, please contact me at my e-mail address. The pictures on my page can only be used under the author's explicit permission.
If you are a member of a Non-Governmental Organisation, or you intend to use it for non-profit educational purposes, please send me an e-mail so that permission can be granted to use the pictures for free.
In any case, please feel free to contact me.