Originally, the web was designed to convey primarily textual information. The HTML language was created to provide basic tools that allowed a document to be written without worrying about how it looked on the page; it was the browser's job to take care of the presentation. Where illustrations were concerned, support was basic but functional---pictures could only be inserted almost as if they were just another block of text, and certainly couldn't be placed on screen with any accuracy.

As the web developed, and expanded the range of types of information that it conveyed, the support for images grew, at first with proprietary extensions created within individual browsers, and later through modifications to the HTML standards. The range of image types that can be used has also grown; whereas the early browsers could only interpret one or two image formats, the lastest browsers can display a huge range.