Comparison of the outskirts’ ellipticities measured on images with and without subtracting the PSF-induced scattered light. Dark-red circles represent galaxies satisfying the ellipticity threshold (after correcting for the PSF effect) for stellar halo identification, while blue circles represent galaxies with power-law surface brightness profiles in the outskirts but do not satisfy the ellipticity requirement for halo identification (see Section 3.3 for details). Gray circles indicate galaxies without stellar halo detection. This comparison demonstrates the necessity of subtracting PSF-induced scattered light for reliable ellipticity measurements and stellar halo selection.