Enigma Theme – avoid bad request

Hi

I have a new install of the Enigma theme at https://www.house-for-fast-cash.com

I ran a speed test on pingdom and there is an alert “avoid bad requests”

The following requests are returning 404/410 responses. Either fix the broken links, or remove the references to the non-existent resources.
https://www.house-for-fast-cash.com/wp-content/themes/enigma/images/shadow1.png
https://www.house-for-fast-cash.com/wp-content/themes/enigma/images/shadow3.png

Any ideas how to fix or remove this?

Thanks

Clare