  The new generation of VLTI instruments (GRAVITY, MATISSE) aims to produce
routinely interferometric images to uncover the morphological complexity of
different objects at high angular resolution. Image reconstruction is, however,
not a fully automated process. Here we focus on a specific science case, namely
the complex circumbinary environments of a subset of evolved binaries, for
which interferometric imaging provides the spatial resolution required to
resolve the immediate circumbinary environment.
  Indeed, many binaries where the main star is in the post-asymptotic giant
branch (post-AGB) phase are surrounded by circumbinary disks. Those disks were
first inferred from the infrared excess produced by dust. Snapshot
interferometric observations in the infrared confirmed disk-like morphology and
revealed high spatial complexity of the emission that the use of geometrical
models could not recover without being strongly biased. Arguably, the most
convincing proof of the disk-like shape of the circumbinary environment came
from the first interferometric image of such a system (IRAS08544-4431) using
the PIONIER instrument at the VLTI. This image was obtained using the SPARCO
image reconstruction approach that enables to subtract a model of a component
of the image and reconstruct an image of its environment only. In the case of
IRAS08544-4431, the model involved a binary and the image of the remaining
signal revealed several unexpected features. Then, a second image revealed a
different but also complex circumstellar morphology around HD101584 that was
well studied by ALMA. To exploit the VLTI imaging capability to understand
these targets, we started a large program at the VLTI to image post-AGB binary
systems using both PIONIER and GRAVITY instruments.
