For 2D images Plotly.js v1.51 has a new trace called image.
For 3D data you could use surface, isosurface and volume. Please refer to @empet 's examples New 3d trace isosurface and namely slices at https://plot.ly/~empet/15150/brain-and-brain-slices-defined-via-gois/#/
Also see https://github.com/plotly/plotly.py/issues/1827#issuecomment-551107783