Learning html tags will be your first task when learning web design. The tags are easy to remember. The most important tags are: the html, head, title, style, body, and script tags.
Let's say you have an ordered list which contains 6 items. The items are the children of the ordered list and can be referred to as 1st child, 2nd child, 3rd child, 4th child and so on. Oh yess ... there are orphans and grandparents but we'll save that for another day.
Once any item is placed onto your webpage it is surrounded by layers. The innermost layer against your element [ an image in this case ] is called padding, the next layer is the margin and the outermost layer is the border. These layers vary in thickness and can be measured in pixels, ems, or percent. OK onto the HTML tags.