pyRenamer allows you to specify a template upon which to form the new file names. Before you apply the changes, you can click the Preview button and see how will look like the file names after renaming. As a template you can specify different lookup, for example, numbering, date, size (for images), a random number, and so on.
The program has the ability to rename graphics files and music based on metadata extracted from the file.
Installation latest version into Linux Mint:
sudo apt-get install pyrenamer