Maybe you have used an nexus 7 and are looking to move your own movies and pictures to and from Mac OS X. With Google's free Android File Transfer software, Mac users have the simplest solution to view and transfer files between Android devices and Mac, similar as using an FTP program.
* Download Android File Transfer tool from android.com website and install it on your Mac running Mac OS X 10.5 or later.
* Connect the tablet to Mac via USB cable, and the app will open automatically.
* Now you are able to copy, move or delete files and add folders. Due to Androids file system, the file size limitation to transfer is under 4GB.
I have had a testing with Android File Transfer. It does not work on Lion and says "..had close unexpectedly..".