After you have uploaded a file, you may want to change the name of it for easier searching. This can be easily done by clicking on the edit link underneath the file in the file library.
You may end up using a file in a lot of articles and then realize that you actually need a different version of the file. The good news is that by editing the file and uploading a new one, everywhere that you used the file previously will automatically update with the new file. This can be great when you are documenting software that changes a lot. Upload initially and then edit and re-upload whenever necessary.