Difference of the MAG_AUTO measurements from the I₀ and I₁ images, vs. . Top left: Δmag as a function of the I₀ magnitude for the LSST-like and CSST simulations. The lines show the median of Δmag. Top right: distribution of Δmag. Bottom: three examples of galaxy images illustrating the impact of blending with the top for CSST I₀ (left) and I₁ (right), and the bottom for the corresponding LSST-like case. The SExtractor Kron ellipses are overlaid for the detected objects.