L-curves of the MiRA images reconstructed using the VLTI/MATISSE 3 Puppis data, and for each spectral band. The median curve resulting from the data binning performed by MYTHRA is shown by the solid black line, and the pink cross indicates the inflection point, corresponding to the optimal hyperparameter value. Each coloured dot represents one of the 3360 reconstructed images generated by the PYRA grid. The colourmap reflects the pixel size value used to reconstruct the circumstellar environment. Top plot : L-band. Centre plot : M-band. Bottom plot : N-band.