[saryant]

This is the first time I've read about the image data URI technique. Is this a common practice?

[pbhjpbhj]

I'd say spriting is a lot more common - http://www.patternify.com/ uses the URI technique, came up on HN today.

I've been using it for a few years for a vCard SVG image (that is probably next to useless).

[andrewjshults]

I've seen it used most commonly for framework assets (e.g., icons in profiler bar, exception handler pages, etc.) so that you don't have to clutter up your public directory with assets that will never be served on production. Otherwise, spriting + a pre-processor/asset pipeline gives nearly the same main benefit (reduced HTTP requests) with a lot less developer work + allows for caching.