images mysteriously disappeared in multisite

I swear, I didn’t touch it!

All of the sudden there are images on my site that are not showing up.

The site is https://signaturesongsbyfiz.info/

There is a bulleted list that is supposed to be showing “check” icons for each of the bullet points. East list item is given a class property that refers to the .css stylesheet to tell it where to get the image from.

The stylesheet shows https://signaturesongsbyfiz.fiz4ever.com/files/2013/11/check.png as the URL for the image. However, the actual image is in this directory:
/public_html/wp-content/blogs.dir/3/files/2013/11/check.png.

I did not set up this site. I am completely new to multisites. I didn’t even know what they were until yesterday.

Any help would be appreciated. Obviously, I’m trying to figure out what went wrong and how to fix this problem.

Thanks.