Broad-band images of the galaxies of the sample. The field of view is 1′ × 1′, while the inner box marks the area covered by the emission line maps presented in Figs. 6 to 13. All images are shown in logarithmic scale. North is up, east to the left. Haro 11: R-band, extracted from the image service of the Centre de Données astronomiques de Strasbourg (CDS) portal; Haro 14: B-band, 60-inch telescope on Mt. Palomar (Gil de Paz et al. 2003); Haro 15: B-Band, JKT 1.0 m (Cairós et al. 2001b); Tololo 0127-397: B-band, ESO Danish 1.54 m Telescope (Cairós et al. 2001b); Tololo 1924-416: B-band, du Pont 100 inch telescope in Las Campanas Observatory (Gil de Paz et al. 2003); Tololo 1937-423: B-band, du Pont 100 inch telescope in Las Campanas Observatory (Gil de Paz et al. 2003); Mrk 900: B-band, 60-inch telescope on Mt. Palomar (Gil de Paz et al. 2003); Mrk 1131: POSS-II frame extracted from the image service of the CDS portal.