Left: comparison between [O II]-based sizes R_e from MUSE (at FWHM ≈ 0.7″ resolution) versus H-band continuum R_e, ⋆ from HST/F160W at ≈0.15″ resolution, for the full sample of 494 SFGs, where the points are color-coded according to Eq. (6). The top panel shows the relative error δR_e/R_e as a function of the effective S/N (see text) and the side histogram shows its distribution. The gray errorbars represent the 3σ_t statistical uncertainties. This shows that our MUSE-[O II] sizes are of sufficient accuracy down to ≈1 kpc, provided that the effective S/N is ⪆3. Right: sizes R_e (from HST/F160W) as a function of redshift for 182 galaxies in the MUSE UDF-mosaic field whose effective S/N is sufficient. The gray region represents the region probed by Swinbank et al. (2017). The dashed line represents ∝(1 + z)¹. The vertical error bars are 3σ.