WebmasterT on "Author Image Upload Error"

I recently created a new "Author" for my WordPress powered website.

When the Author uploads a image, WordPress adds information to file name:

For example, when this user adds an image with this file name:
grant-gustin-the-flash-01-350x164.jpg

WordPress creates this:
grant-gustin-the-flash-01-350x164-e1384812224671-350x164.jpg

Why is WordPress doing this and how can I fix this problem?