Stack of the 37 galaxies with 3.27 <z_spec< 3.40 in the U (left) and R-bands (right) for the VUDS-LBC/COSMOS, Q0933, and Q1623 fields. Other objects detected in the R-band, but not associated with the galaxies at z ~ 3.3 (at the centre of the thumbnail) have been masked both in the U- and in the R-band image using the segmentation map derived from the R-band. The size of each image is 14 arcsec by 14 arcsec.