Currently in use the bootstrap frame structures, web pages, the processing images of reactive meet a problem now
Content in order to made the concise and beautiful pictures, content width in about 1200 px, the rest are all background, if directly into a reactive images will directly, the two sides of the filling will follow, if make a div background with background - size: cover resizing images would have been abandoned, is there any way that when the page down to 1200 px on both sides of the filling after abandoning, responsive to narrow in a fixed image, is to write js