You can also do this for existing images. As for the length of the replacement text, take a look at what WCAG 2.0 says: The alt attribute value must be less than 100 English characters in length or the user must ensure that the replacement text is as short as possible. Das ALT-Attribut wird bei Bilddateien auf einer Webseite hinterlegt. alt. Functional images Often images will be wrapped in a anchor link element () or a