If the image is relevant to the content of the document, you must supply alternate text that will appear in text-only browsers, and that will appear in other browsers when an image is loading or when image loading is disabled.
Si le imagine es pertinente al contento del documento, tu debe fornir texto alternative que parera in navigatores de solo texto e in altere navigatores quando un imagine es in cargamento o quando le cargamento del imagines es disactivate.