[sociallocker]The alt tag is an attribute (“alt tag” is not technically correct, it should be called “alt attribute”) of an image used in a website. The alt tag role is to describe the image and the function of the website in which the image is used. In addition the attribute is very important for SEO, since search engines use the alt tag to better understand the page in which the image in inserted.
How to optimise the alt tag
The alt tag should always be optimised since it is one of the most important elements that search engines use to index webpages. The alt tag should give more information on the image and the content of the webpage in which the image is inserted by using primary and secondary keywords. Never stuff the alt tag with too many keywords or it won’t have the same positive effect on your SEO.
The image of the Just Eat logo in the UK homepage has the following alt tag: “Order takeaway from 20,000+ restaurants | Just Eat”. The alt tag contains multiple keywords while stating organically the content of the page on which the logo is placed.
<img alt="Order takeaway from 20,000+ restaurants | Just Eat" src="//dy3erx8o0a6nh.cloudfront.net/images/logo-just-eat-2016_x2.png" width="153" height="30">