If there is no alt tag, search engine doesn't understand anything from the image.
That's why you should use alt tag on your all pictures, which you use in your website.
For example your computer's IP address is 188.8.131.52. Webmasters, publicists and ad networks assess your website that base on alexa rank estimation of your site or online journal.
The main source of visits is direct access to the site.
Other wise this will affects your website negatively.
It's very important to use pictures on your website to bring up the main concepts of your website. Search engines understand the pictures by their alt tags.
The links on the other websites are called external link.
You should not have too much external links on your website.
2.4% of users visit from a search engine, while 37.8% via a hyperlink, and 59.7% come directly - i.e.