\starttext

    \setupfloat[figure][default={left,nonumber}]

    \placefigure{my figure caption my figure caption}{\framed[width=4cm,height=1cm]{}} \input tufte
    \placefigure{my figure caption}                  {\framed[width=4cm,height=1cm]{}} \input tufte

    \setupfloat[figure][location=left]
    \setupcaption[figure][width=max]

    \placefigure{my figure caption my figure caption}{\framed[width=4cm,height=1cm]{}} \input tufte
    \placefigure{my figure caption}                  {\framed[width=4cm,height=1cm]{}} \input tufte

\stoptext
