how the images audio, video , images storing in android?? r these using database or filesystem????
pls give any suggestion...

Data stored on file system, info stored in DB. you can use MeidaStore to access them.

also how do i access the default wallpapers in the system?

Hi

The media store will give you all images on your system including thats on sdcard. Dont see any flag or property that defines it being default.