Mark Pilgrim traces the conversations that resulted in the IMG tag, with lots of interesting conclusions and observations mixed in. I won’t give away the ending, but here’s one important takeaway:

HTML has always been a conversation between browser makers, authors, standards wonks, and other people who just showed up and liked to talk about angle brackets. Most of the successful versions of HTML have been “retro-specs,” catching up to the world while simultaneously trying to nudge it in the right direction. Anyone who tells you that HTML should be kept “pure” (presumably by ignoring browser makers, or ignoring authors, or both) is simply misinformed. HTML has never been pure, and all attempts to purify it have been spectacular failures, matched only by the attempts to replace it.