Median log size difference of log(M/M_⊙) > 10.85 cluster galaxies (darker symbols with error bars, corrected for residual background subtraction, see text) and of field counterparts at 1.3 < z < 1.8 (shaded rectangles showing the 16th–84th percentile range, see text) with respect to the expected size from the van der Wel et al. (2014) star-forming (left panel) and quiescent (right panel) relations. Median differences are shown for different sub-samples based on Sersic index (symbols as in Fig. 4, or squares for no Sersic index selection) and star-forming (blue colour shades) vs. quiescent (red colour shades) classification (grey symbols show samples selected by Sersic index only, regardless of star-forming vs. quiescent classification; see text).