Possible Hack Solution

Hi everyone, I could really use some help.

If you visit my word press page at:
https://www.lensaunders.com/wp/?cat=48

When you let the page load fully – or put your mouse over the first image, the image will open a ‘slide’ with an advertisement, which I did not put there, with the words awesome screenshot.

This image has arrows that show it:
https://postimage.org/image/sbya1d6yt/

My question. I did not put this there. How can I remove this, and how did this happen.

I am not well versed in word press, but could really use your help getting rid of this.

Thank you.