Do you use the Static Block block to show these images? Use Column Responsive options http://prntscr.com/qdjmx0 . And we would recommend you to show 2+2+2+… or 4+4+4+… images per row for the mobile using Column Responsive options http://prntscr.com/qdjmx0
In other case you will get 3+1+3+1 images if you use 3 columns per row.
