The <img> element lets you add images to a web page. <img>element has required attribute called src, which is similar to the href. The values of src must be the URL of the image. <img> also need a / to self-closing element.

　　<img> exmaple like this :

　　　　 <img src="https://www.exmaple.com/picture.jepg"/> 

Also, the alt attribute is applied specifically to the <img> element as a description.

　　why add alt attibute?

　　1. If an image fails to load on a web page, a user can ouse over the area originally intended for the image and read a brief description of the image.

　　2.Visually impaired users often browse the web with the aid of of screen reading software.When you include alt, the screen reading software can read the images‘s description outloud to the visusally impaired user.

　　note: If the image on the web page is ot one that conveys any meaningful information to a user, the alt attribute should not be used.

　　<img>+alt exmaple like this:

　　　　<img src="https://www.exmaple.com/picture.jepg" alt ="description"/> 

【codecademy summary】html+css <img>