accessibility - HTML img tag: title attribute vs. alt attribute?

Question

I was browsing Amazon and I noticed that when searching "1TB" if you hover the mouse cursor over the stars rating image, you only see the score if using IE. If you are using another browser then the score won't show.

A rating of 3.8 and a rating of 4.2 both show up as 4 stars. Of course a 3.8 stars vs 4.2 stars (76% vs 84% score) could make a difference!

This is because the standard way of displaying alt text is only when the user turns off graphics or when the browser is "read out" (e.g browser for users who are visually impaired). IE however, shows it on hover.

So I think if Amazon is to show it regardless of the user's browser, then title should be used in addition to alt. Would you agree?

Answer 1

They are used for different things. The alt attribute is used instead of the image. If the image can't be shown, and in screen readers.

The title attribute is shown along with the image, typically as a hover tooltip.

One should not be used "instead" of the other. Each should be used properly, to do the things they were designed to do.