CSS Change for mobile device (Story page image cut off page)

Hi
I need some help resolving this issue on the "Sitename story" page the image needs to be scaled to fit the full width of the page or if that is not possible then centred in the page and have black on either side without the white block thats currently on the right hand side.

Please see Screenshot: http://monosnap.com/image/J2co795y5EDXsLdfiVCKnc9im5r6TE

Domain Link: http://tinyurl.com/ojeaxpz

Support access also open

Thanks
Tom