W3c validator: error tag without Alt attribute

Hi, ?is posible to solve this kind of error?

https://validator.w3.org:

“Error: An img element must have an alt attribute, except under certain conditions.

( img src=”https://xxxxxx.com.com/wp-content/plugins/wp-postratings/images/loading.gif” width=”16″ height=”16″ )

Thanks.