When a file is deleted it is moved to the site's recycle bin, like when you delete a file on your desktop or laptop computer. You can access the recycle bin by going to Site Actions > View All Site Content. The Recycle bin is the last item at the bottom of the all site content page.
Click on the recycle bin to view its content.
The recycle bin will contain a list of recently deleted files and information about where they were located and when they were deleted.
To un-delete the file tick the checkbox next to the file and click the Restore Selection button.
Files will remain in the recycle bin for no longer than 30 days. After that time has passed someone from Web and Media Services may be able to retrieve the file from a secondary recycle bin, but we cannot guarantee we will still have it.