For a better SEO, but also not to share your local files names, especially for pictures / images medias, and avoid sharing bad names like 11-finalresult.png in the example, but having a nicer ms-excel-2013-how-to-make-a-table-look-good-resize-columns-to-fit-content.png instead, a good and simple solution is to use the plugin Media File Renamer.
See also WordPress howto install a plugin
Once installed, go in the File Renamer plugin Settings.
There, make sure the option Rename On Save is checked. This will ensure that however your files are named, once attached to your posts, they will be automatically renamed with the title you have put in the description.
Don’t forget to also rename your files already uploaded on your WordPress installation.
Go to Media => File Renamer, and click the Scan All & Show Issues to see which files could use a rename. Click the Rename XX flagged media to have these files with issue renamed.
You can also click the Unlock & Rename all XXX media to have all your medias renamed.