Wavelength dependence of the effective radius for our sample of TNG50 galaxies. Top panel: median value of the half-light radius. Middle panel: median ratio of the half-light radius to the g-band half-light radius. Bottom panel: median ratio of the half-light radius and half-mass radius. In all three panels, the black lines and markers correspond to the dust-affected images, the blue ones to the dust-free images. The dotted lines represent power-law fits to the data points.