trying to use JOSM and I can't see the map in JOSM at 1900m

Hello, I’m trying to edit the map of my city, because there is no data about it. I don’t have GPS equipment, so I am trying to edit my city using JOSM and the AERIAL MAPs provided by Yahoo; but everywhere, including the capital City (Lima, Peru) doesn’t show me any image at less than 6000m (over sea level), well my town is Huancayo(3200 over sea level) and there is no road, nothing!
I don’t know why, but in this case , I can’t draw any line.
Please do you know why is this?
In JOSM I use the zoom tool, and for getting the image with new resolution I click over the Layer Map, and select “Change resolution”
But there is no actualization and the screen turns black, no image, no map.
So how could I edit maps in JOSM?

Does any body know how can I upload a map from other source to draw over it the roads an other elements?

Do you have permission to use that map to trace roads and then add them to OSM? Just having permission for personal use is not enough.