When working with your photos think larger.
and maybe you will even cover trains with them.
So they can be seen by Google Earth like these can.
Artist J-R places photographs of women's faces on the rooftops of the slums of Kibera. You can actually see them from space. Not only is this visually arresting - the photos are printed on waterproof strata so that they literally protect the dwellings underneath.
"The train that passes on this line through Kibera at least twice a day has also been covered with eyes from the women that live below it. With the eyes on the train, the bottom half of the their faces have be pasted on corrugated sheets on the slope that leads down from the tracks to the rooftops. The idea being that for the split second the train passes, their eyes will match their smiles and their faces will be complete. You must watch the video on his site..it is amazing to get to know a little bit about the women in the project.