MiRA image reconstructions for the MATISSE N band for the 8.5 (top row) and 11.3 μm (bottom row) wavelength region. Magenta (cyan) contours indicate where the signal is 5 times (30 times) the estimated background noise, and the inner red contour encapsulates the regions where the S/N is in the top 10% of all values across the image. The innermost dashed cyan circle represents the photospheric diameter from Paladini et al. (2017, see our Sect. 2), while the outer circle corresponds to the photospheric diameter scaled to 12 μm, based on the size ratio of the 2 and 12 μm mass-losing dynamic models in Paladini et al. (2009). Both are marked with a dashed blue line in the radial profile plots. The sectors marked by the dotted white lines are the regions used in the plotting of the radial profiles presented in the bottom row. The images were normalised with respect to the highest intensity pixel and re-centred on the maximum local average intensity, computed using a square kernel with a radius of 3 mas. The white ellipse shows the estimated beam size and its inclination at each wavelength interval.