Fluidity
Image Lightbox, Responsive and Touch‑friendly — Osvaldas Valutis
Responsive background images with fixed or fluid aspect ratios – Voormedia
What's the easiest way to scale background images in responsive layouts? We use an old technique and enhance it to fluidly change the aspect ratio of background images.
Where are the Mobile First Responsive Web Designs? « Cloud Four
rlightbox – a jQuery UI mediabox
Responsible responsive images