If you're on any of the recent versions you have 3 sources and 4 options to choose from for the automatic backgrounds. Tools>General Options and then the Mapping 1 tab. At the bottom is where you can turn them on/off all together. Once they're on, you can have it on automatic and pick the "best" of the 3 free sources which may or may not be the best for your exact field location. You can also choose one of the specific sources if you find one of them is consistently better. Automatic can switch from field to field or map to map depending on the resolution available.