(a1) and (a2): HMI continuum image and LOS magnetogram for the active region NOAA 12673 at 09:01:30 UT on September 6, 2017. The orange contours mark the flare regions. The red region indicates the area of concentrated WL pixels. The green denotes a single isolated WL pixel, while the blue denotes only two conjoined WL pixels. (b1) and (b2): Statistical plots of the WL enhancement ((I_p − I₀)/I₀) for the isolated single-pixel region and the adjacent two-pixel region, respectively. Here I_p and I₀ refer to the HMI continuum intensities at the peak of WL flux and before the flare at a pixel.