Hi, everyone. I'm looking for ways to install unframed photographs onto wooden walls. I especially fancy a kind of "fasteners" I came across in various exhibitions from time to time. They are rectangular in shape and made of transparent plastic. There is a hole on one end for applying the screws, and the other end contacts with the print. The thickness on this end is also thinner so you can install matted prints. With several of those on the front of each side of the photograph they can affix it onto the wall without leaving any marks on it (light pressure mark I doubt). I don't know what it is called. Where can I get access to buy this kind of fasteners? Sorry for my inexperience in installing exhibitions (and my poor english), I hope you can understand my description. Please advice.

Cheers,
Dustin