Currently converting my fixed width site to responsive, I'm unsure on how best to handle one specific element.
I have some images the full width of the main text column, coded as the image plus 4px padding and a 1px border.
I'd quite like to keep that 4+1px proportion even on small displays.
What's the sensible way of doing this? Or is it simply not possible to retain px within a responsive design, and I therefore have to convert to %?