No, I don't want image display. I want to replicate Atom's inlining editing features. Did you look into that? This is one example:
https://discuss.atom.io/t/expand-css-rules-inline-html/12437
I don't think that inlining feature really help much. Generally, if you want to access a css element in Emacs, you jump in, edit and jump back in an instant to see your result.
See also web-mode: http://web-mode.org