Anyone who clicks on the link will be taken to a web page consisting of just the picture and nothing else. A picture displayed in this fashion is called an in-line image . You could replace the number 5 with a larger or smaller number for a thicker or thinner border. The alternate text is not displayed on browsers that are displaying the picture. Avoiding long waits.
Large pictures take a long time to load.
But someone else far away, viewing your web page for the first time, may have to wait a long time to wait for your images to load. Therefore, you generally should not use more than a handful of images on one web page, and you generally should not embed large images as in-line images. Here is a compromise technique that many people like to use. Create two versions of your picture. When using thumbnails, I recommend including a small border, as in the example above.