Tried to get the alt tag to work, which I know how to do. Done it a millions times but in differenet markup. Just cant get it to work in this context. Anyways thanks for all your help, I’m out of time so cant make anymore improvements.
Good idea: like all images, it requires alt text (instead of a value attribute) which can be shown when images don’t load.
However I would go ahead and have a hover/focus style and add cursor: pointer to it as well (for any browsers who refuse to do that with images). It needs to act like a button so people know right away that it is, indeed, a button.
You know there is an <input type=“image” /> … right?
That would also be better suited in this case because it still shows up when a non-css capable visitor comes by, whereas your css background will disappear in that case.