However, when it comes to attractive layout, a picture is worth a thousand words, which is fine, except for the fact that pictures generally also require a thousand times as many bytes to be transferred.
A picture can be included using an HTML command such as:
<img src=a_thousand_words.gif>In this case, this tells Mosaic that there is a picture called
A more complex example is:
<img src=http://www.cs.ucl.ac.uk/uk/london/tower_bridge.gif>In this case, the image is specified with a complete URL, which tells Mosaic exactly where to go to fetch the picture. Note that the data for the picture does not need to reside on the same server as the document that it is embedded in.
Also note that we've omitted the quotes from around this URL - although it's not a bad idea to add them for the sake of clarity, or for URLs containing odd characters such as spaces, they're not strictly necessary in most circumstances.
In order for an image to be displayed in a page of a document, it must be in one of a small number of formats. However, not all formats are displayable on all browsers.
Although many other image formats are viewable using an external viewer program, they are not necessarily viewable as embedded images on your browser. More details on MIME content types, how they are servered and how the client interprets them are in chapters 4 and 5.