How to add image to default mega menu

Hello!

Need some help with a few matters.

Header
1) As per title.. how do i add an image to a column of a default mega menu?

2) On my Safari browser, the mega menu shows up when you hover on the links. On my Window laptop when i use Google Chrome, i need to actually click on the link to expand the mega menu. It does not expand when i hover on the links. Is there a fix for this?

Footer
3) How do i add social media icons to the footer widget area? I know i can download a plugin and place it at the footer widget area but i understand that Sparkle has a built-in social media icons located at the header. I want to make use of that and add a slightly bigger version at the footer widget area.

4) On the same note, as i am designing the footer widget area, how do i add horizontalnavigation links (About, Privacy, Advertise, etc) on the footer widget area? Do i add a html widget and do my own styling & linking there? I tried adding a page widget but it turns out to be a vertical navigation links. Any easy way to do it?