drupal files directory I have a Drupal site and I am unsure of how the files directory works. 

It seems at the moment all files uploaded to the site go to the files directory. If I create a new node and upload fish.png which goes to the files directory another user also uploading a file called fish.png will overwrite my file. 

Have I missed something here???
You can see the how to set the file system settings on File system settings. You can also change it, and specify the other folder for the files as per your requirement.