Source

picrename / REAME.txt

This is a small utility to rename all pictures in a directory to have an
ascending order.

For example:

    DSC03606.JPG
    DSC03607.JPG
    DSC03608.JPG
    not-a-picture.txt

Will become:
    1.JPG
    2.JPG
    3.JPG
    not-a-picture.txt