There is noplace within walking distance. WDW is just too darn big.
There is a
WalMart quite close, on SR 535, about 2 miles south of the Crossroads shopping center that FranP mentioned, but even if you wanted to walk the distance, it's incredibly dangerous, because there are no sidewalks and the traffic on SR 535 is very heavy and moves very fast.
There are also several Walgreens stores in the WDW area, all of which have 24-hour photo centers that will download your pics to CD for only $3.99, for as many pics as the CD will hold. Of course, none of these are within walking distance, either, but the closest is also on SR 535, about 1/4 mile north of the Crossroads.