Average brightness radial profile (black line) for a point source (SZ Cha, left) and an extended source (T54, right) compared to the observational PSF radial profile (red line). The error bars are the rms of the values. All considered sources present the same behavior as SZ Cha except for T54, whose observed radial profile is clearly above the PSF profile, indicating that this source is extended and all others are point-like in Herschel images.