Problem With Footer Featured Post Image Size

Hi, I am new on Wp, I am setting up my website, but now i am facing a problem,
I have theme of Themeforest, and i want to add Featured Post widget at the footer of my theme, so when i do so i successfully add the widget, but i am not getting full width image , while in their demo pic they have full image.

I have changed to different images in post but not luck kindly help

Here is my home page

and Screen Shot