Extract to image file country side map

Hello everybody,

for a university project I am attending, I am trying to overlap the UK gas network with the openstreetmap base layer (the one that shows inhabited regions, countryside and so on) in order to identifiy the regions were the gas pipes pass in inhabited regions. To do so, I wanted to download the map of Great Britain and try to overlap it with my network map as a image file (.png or .jpg). The problem is that I would like to have a very high resolution and I am not sure I can extract such an image file from OSM. Is there a way to do it?

Thank you a lot!!!