如何将$ row作为图像回显？

Question

I am trying to echo the average ratings of products but instead of numbers, I would like to echo it as star image. I've tried solutions suggested and none of them seemed to work.

I've tried:

<a href=\"{$row['average_rating']}\"><img src=\"IMAGE_URL_GOES_HERE\" /></a> 

and of the like and non of them seemed to work.

This is my image code:

<img src='../public/images/star.png' height='20px' width='20px'/>

My function.php codes:

function reviews_average(){

            $avgproduct_id = escape_string($_GET['id']);

            $avgquery = 
"SELECT avg(rating) as average_rating FROM reviews WHERE product_id = $avgproduct_id";
            $avgresults = query($avgquery);
            confirm_query($avgquery);

            while($row = fetch_array($avgresults)){

            ***This is the one I want to display as an image*** 
            $avgratings = "{$row['average_rating']}";
            ***END*** 


            echo $avgratings; 
   }
 }