% images from imagemagick suite

\starttext

\startbuffer
    \externalfigure[mask-001.png][height=5cm,frame=on]
    \externalfigure[mask-002.png][height=5cm,frame=on]
    \externalfigure[mask-001.png][mask=mask-002.png,height=5cm,frame=on]
\stopbuffer

\typebuffer \getbuffer

\stoptext
