CommonMark has yet to implement any nifty image features. MultiMarkdown has some great ones:
The basic syntax for images in Markdown is:
![Alt text](/path/to/img.jpg "Optional title")
[id]: url/to/image "Optional title attribute"
In addition to the attributes we can use with MultiMarkdown (see thread here), MultiMarkdown also adds a few additional things. If an image is the only thing in a paragraph, it is treated as a block level element:
This image (![Alt text](/path/to/img.jpg))
is different than the following image:
The resulting HTML is:
<p>This image (<img src="/path/to/img.jpg" alt="Alt text" />)
is different than the following image:</p>
<img src="/path/to/img.jpg" alt="Alt text" />
The first one would be an inline image. The second one (in HTML) would be wrapped in an HTML figure element. In this case, the alt text is also used as a figure caption, and can contain MultiMarkdown syntax (e.g. bold, emph, etc.). The alt text is not specifically designed to limit which MultiMarkdown is supported, but there will be limits and block level elements aren’t supported.
That’s already been discussed before.
Yeah, the concept of images has been discussed previously, but nothing’s been mentioned of MultiMarkdown’s specific implementation.
That said, in general, there’s been plenty of discussion.
But, everyone just keeps discussing.
When does discussion become implementation?
Do 10 other people have to submit duplicate spec suggestions before discussion becomes action?
As far as I can tell from your example, Multi-Markdown is equivalent to Pandoc in this regard and that has been discussed in the thread I linked to.
@jgm and others also have stated many times that version 1.0 will basically be original Markdown with inconsistencies, ambiguities and errors removed – there’s still a lot to be done. Mandatory additions and optional/modular extensions will come later. Many existing flavors and their syntax extensions as well as proposals have been collected in the wiki.
Standardization process often feels terribly slow, but it’s often worth it.
I hear you. I think it’s worth it too.
I suppose, then, that there is some governing body of like ten of you guys who are going to decide on all this stuff sometime soon?
TL;DR: When does the discussion end and implementation begin?
Implementation has already begun! There a dozens of Markdown producers and consumers out there, many of which started life before CommonMark was a thing. The point of CommonMark is to produce a “standard, unambiguous syntax specification for Markdown”, which has been lacking hitherto.
At this stage of the game, CommonMark is just trying to get a standard syntax that everyone can subscribe to, and that’s still hard. Maybe one day new features will start with discussions in CommonMark, become a part of the standard, and then be implemented by others, but if that day ever comes it’s not today.