Can I add alt tag to custom css?

Is it possible to add alt text to custom css in this instance:

.outer.top{
background:url(%resource(photo-name.jpg)%) 50% 50% repeat; background-size:cover;
}

???

No. Further more, alt tag is a property for img.

Thanks for your reply! OK, is there a way to add an alt description in the above instance?

alt text can only be added to img tags. You have there n background image, so you are not able to add an alt tag there.

Are you able to change the code of the HTML element, which has applied the CSS class .outer.top?

I think that is beyond my skill set. I’m using Aptenon theme and the custom CSS refers to a banner image that is different on each page: www.typarke.co.uk.

The question is, why you want to add an alt text to a background image?