Problem with my tribute page, responsive image

https://codepen.io/kleub51/pen/zYKmrwE?editors=1100

im very convused as to why the error is popping up. My resposive images are working and I am now doubting myself.

When a test fails click the red button to see which test(s) are failing and text to help you correct the issue. (Be sure and read more than just the first line of the failing message.)