Hello,
1) Are you talking about mega menu http://prntscr.com/w8gglc ? You can change the width of the mega menu here http://prntscr.com/w8gikr It will increase the total width and the width of the columns that allows to show titles in one line.
2) Add these elements to next row http://prntscr.com/w8h343 I have created an exmple.
3) You can manage the image size using bg settings http://prntscr.com/w8h5lj Choose the one that will suit your needs.
4) You can add it in 2 ways: a) using border http://prntscr.com/w8h6oa b) using Divider element http://prntscr.com/w8h7qr Choose the one that suits your needs most of all.
Regards
