VLASS contours of the three sources from the Liao & Gu (2020) sample with VLASS sizes larger than 50 kpc. The ten red contour lines are logarithmically spaced between ∼5σ of the local noise and the maximum flux of the source. The green dashed lines are negative contours at −5σ to −3σ. The background images are from the SDSS i band. The vertical bar at the bottom indicates a length of 50 kpc at the redshift of the source.