The HTML img tag shows an image.
<img height="90" width="90" src="angry.gif" alt="Angry" title="Angry Smiley" />
The height and width tags are added for speed.
“When the height and width tags are included the browser will automatically know the size of the image. As a consequence it will be able to hold a place for the image and load the rest of the page contemporaneously. Apart from the improvement on the load time of the page this method is also more user friendly since the visitor can start reading the text or other information while the image is being downloaded.” From Daily Blog Tips
Search engine optimization (SEO)
The title tag is added for seo purpose, but alt tag is more important in seo.
“Make sure that your TITLE and ALT tags are descriptive and accurate.” From Google
The title tag is also added for accessibility, with a maximum of 100 chars.