Context : OnMedia
Here's a nice bit of interpretation of the role of IMG in the evolution of the web.
Now, here's a key point: the developers of Mosaic at NCSA didn't know it, but the introduction of the IMG SRC tag in 1992 was going to do more to change the shape of 21st century politics than anyone could imagine. Because it opened up the possibility of using the web for graphical content, including magazine publications and porn. As we all know – it's a cliche – new communication technologies catch on for the first time when they are used for the distribution of pornography. This in turn demands mechanisms for payment and for billing users, which ends up creating spin-off industries like the payment service providers, and in turn brings in mechanisms that can be used by other types of business. That one variant tag catalysed, ultimately, the commercialization of the web.