Postage stamp images of the UDGs of our sample in r′-band, all shown in the same brightness scale (logarithmic scale between “−27.8” mag arcsec^-2 and 24 mag arcsec^-2). In the right corner shown are the name, the absolute r′-band magnitude M_r′, the effective radius R_e in kilo parsecs, Sérsic n, axis ratio b/a and the projected cluster-centric distance D_cen. The postage stamps have different sizes on the sky, and therefore 1 arcmin scale bars are shown in the lower left corner of the images. FDS11_LSB1, FDS11_LSB2 and FDS12_LSB3 do not appear in any previously published works. However, FDS11_LSB1 and FDS11_LSB2 have also been identified in Lisker et al. (2017), although there only FDS11_LSB2 is considered as a galaxy.