Tricking image src in yoast SEO

I am using WordPress and want to ask a question regarding YOAST PLUGIN.

my focus keyword is feedback.

TO REMOVE THE FOLLOWING ERROR.

The images on this page contain alt attributes with the focus keyword.

IS IT A GOOD IDEA TO USE img src="#"?

<img src="#" alt="feedback">

Please give me a good advise on this.

via Chebli Mohamed