Cell phone coverage is getting better. In the region I fly more often I get signal about 40% to 60% of the time. On the other hand, most meteo images that are useful in flight are small in size (~10⁴ bytes) and have local coverage (few hundred miles at most).
Here is one example of an age coded lightning map that allow us to see the movement of convective systems. It is updated in 2 min intervals at the website:
A "simple" way to implement meteorological capabilities is leave to the user the input of his/her favorite URL pointing to a meteo image (precip, lightning, cloud tops, whatever). Associated with it, the user may define a linear georef (2 points, 2 coordinates) for such images and a refresh (download attempt) time interval.
A flag can warn the user that last download attempt was unsuccessful and the map is getting old - but still better than those from preflight weather briefing. Availability of directly downloadable images may be an issue.
A fifth FIF screen with a recently dowloaded meteo image can make the difference to divert wisely and get us out of trouble.
clear skies,
Marcos