Top: NIKA maps of MACS J0717.5+3745 at 150 GHz (left) and 260 GHz (right). The gray contours show the significance in units of standard deviation. They are multiples of 2σ at 150 GHz and 1σ at 260 GHz, starting at ±2σ. Both maps have been smoothed to have the same effective resolution of 22 arcsec FWHM, as represented by the white circle on the bottom left corner of the maps. The regions defined in Table 2 are shown as gray dot-dashed circles. Bottom: same as top-panel figures, in the case of half difference maps computed from two equivalent sub-samples. The steps between contours is 1σ for both frequencies.