I suppose that for a hundred or so years that general definition worked as a metaphor to describe a new technology and medium and what could be done with it, whether that be still, animated or in motion images.
But sometimes metaphors stop working as a way to mentally conceive, and build off of and from, new technologies.
When the "web" first came into mass consciousness and culture, the metaphor that was initially used was the web "page". By using the word "page" as the defining principle, we then logically used other pages that we knew - magazine pages, in particular - to define what web pages were and could be. Interactive magazines, in a way. So, perhaps, the initial wave of web innovation was about making better magazines - interactive, specifically targeted pages for sure, but pages and the attributes of pages nonetheless. Design - user interface and experience - then also followed this line of thought. Thus, it's no surprise that the first search engines used directories - indexes, of a sort - as their jumping off point metaphor for organization.
It took a while to bust out of the "page" metaphor for web services experiences, maybe 10 years or more. And one could argue that the page metaphor itself was limiting, and then the results therefrom were also limited. Ultimately, the stream and other ideas became dominant, and what was (and still is) exciting about those is that they feel more native to the Internet (and mobile). There is no strong analogy for an analog stream experience.
I think we are in the same place right now with "drawing with light." While functionally that definition may still be correct, what words do we use to make sense of a "drawing with light" that later disappears (Snapchat)? Or that moves and is remixed (animated gifs)? These things are no longer designed per se to capture and be archival. They are meant to enhance current experience.
Or, how do we think about new forms of medical imaging, like figure 1, which take an image (or an ekg, or xray) that is about a local, health experience, and broadcast it all over the world for advice, consensus and, yes, ego? Or Epibone, which uses 3D images to grow bones. What about Mapillary - crowdsourcing street level photos of every place in the world. What do we even call a map once we have that? Similarly, Hivemapper, which is a network of social flying cameras. Finally, the idea of "drawing with light" hardly captures something like Cornar which attempts to record what is beyond the line of sight.
And, once images are digital, and copying them becomes trivial, how do we think about ownership, attribution, and things like that?
Luckily, smart people are thinking about this. Evan Nisselson's LDV Vision Summit (http://www.ldv.co/visionsummit/) on May 19 & 20 in NYC, for one, is two days exploring specifically and only this. New metaphors - computer vision, artificial intelligence, deep learning - that may help. It should be really interesting, and Evan and I will be talking about these themes at the event.
What's great is that we are busting out of the limited, existing "incumbent" metaphor, and inventing new things based on what may now be possible. We'll just need some new words to describe them.