Yes. \placefigure is the old syntax. \start…\stopplacefigure the new one. The new one uses a the key=value syntax also present in other MkIV commands. Compare:
\startplacefigure [title=Lorem, reference=fig:lorem] … \stopplacefigure
\startchapter [title=Lorem, reference=sec:lorem] … \stopchapter
They are both supported, I personally stick to the new variant. I find the interface much more memorable.
I guess, I do not understand the relation completely. Please compare the following -- startcode -- \starttext % \chapter{One} \input tufte \placefigure[margin,none]{}{Let's put some text of at least two lines.} \placefigure[none,margin]{}{Let's put some text of at least two lines.} \input tufte \stoptext -- stopcode -- The first one works as intended, the second one does not. Also, I cannot figure out the equivalent new syntax. I tried 'caption=none' and 'location=none'. But even if the latter one would work, having a caption (or not) and placing the figure on the page are two different things? Andy