Mantra Theme – problem with center images, mobile view, footer

Hello
I have 3 questions about the Mantra Theme:

1. When I have the mobil view enabled, the images I have added in the “Presentation page” under the folder “Bottom text 1″ is not responsive. I have tried to put the relativ sizes, but it seems like that this is not supported in the field “Extra text 1″ under the folder “Presentation page”, because it’s just erased. How can I solve this?

2. I also have a problem with centering images that I’m adding under “Buttom text 1″. I have tried to type in html code for centering image in the “Button text 1, but it doesn’t show up in the webpage, and when I going back to edit mode, the code I typed have disappered. I have tried to use the code <center><img src=”imgName.jpg”</center>.

3. I also wonder if it’s possible to create a footer to be shown under “Extra text 2″?

I would appreciate if someone could tell me if there is any solution to this problems and give me a step to step guide, because I’m new to WordPress and Html/CSS coding. The webpage is http://www.seoc.no