Examples of substructure detections using the optimal (black contours) and intrinsic (yellow contours) approaches. Galaxies are sorted from left to right by increasing redshift and split into three intrinsic substructure classes: clumps, moderately large, and extended (see Sect. 4.2). For each galaxy, we show the image (F277W for 1 < z < 2 and F444W for z > 2) and its residuals below. Red pixels correspond to positive residuals and blue pixels to negative ones. The scale of the residuals is set to ±2σ, with σ the local background fluctuations. In each image, we show the PSF FWHM at the bottom right and upper limits on the area of substructure classes as gray squares at the top right. The residuals show the detection area, highlighted with a thick green contour.