[mddw]

It should not.

An outdated computer/browsers sucks at resizing jpegs. A two year old high end Android smartphone too.

Minimizing HTTP requests, avoiding FOUC, using only one version of JQuery (or, even better, none), using CSS sprites... there are countless optimisations which are more important and seldom used.

Retina is a buzzword and a buzzword resolution. If you target the 0.1% rich hipsters, yeah, it's important. If you've real users browsing in 1024x768 on a four year old laptop and a 2Mbps broadband, it's not.

When Amazon'll use Retina img, that's when it'll be a standard practice.

[Osmium]

Which is a fair point, but it depends who you're targeting: if affluent users are more likely to have high-DPI devices (iPad 3, most smartphones, high-end MacBooks), and they are, then you're going to have to make your site 'retina-ready.' And it's a mistake to thing this is just a young, tech-savvy issue. How many older people are buying iPads? Do you think they'll notice, subconsciously or not, if your site looks a bit crappy?

I have a hard time believing it would be a significant issue to do a 2x image resize, especially if you provide exact image dimensions in your img tag to start with to avoid the renderer having to wait until the image has downloaded to layout the page properly. In any case, I think someone should do some benchmarks to see what kind of an issue it is in practice.

Either way, it's not a bad thing to be forward thinking with design. The amount of 'retina' devices in the world is growing exponentially. At the moment, it's largely an Apple problem, but with high DPI panels now on the market it'll soon be industry-wide.

[mddw]

Show me some A/B testing showing a conversion increase when Retina proofing your website.

Old people with an iPad3 won't see the difference between a non retina and a retina website. They'll see which is the fastest and the easiest to use (because usually, pixel perfect guys are not too smart about UI.)

Retina-ready is a scam. We have neither the tools (SVG support too weak, no <picture> element, no good navigator.connection...) to provide a meaningful retina experience while respecting other users.

Speed trumps "beauty". Most often.

[lttlrck]

You say show me the evidence for A/B testing and then state "Old people with an iPad3 won't see the difference between a non retina and a retina website." where is your evidence?

Anyone old or young that cares about speed of browsing will be running the latest browser, with good upscaling...

Retina isn't a scam, however putting an SEO spin on the need to even consider preparing for the future is

[dvhh]

So why stop at x2, if you want future proof why not store your images at x10 just in case. Isn't it more of a browser problem if they got crappy upsampler.

[barrkel]

The cost of doing it always is primarily in extra memory used on the client, while the quality loss from poor client downsizers should not be too bad, particularly if you target 2x resolution.

IME the best bandwidth optimization is an adblocker :)

[dmorgan]

>An outdated computer/browsers sucks at resizing jpegs.

Most of us don't care about those anymore. Anything older than IE8 is out in modern web design.

>A two year old high end Android smartphone too.

Those matter even less. Two year old is near end-of-life, since people get new contracts. And Android, despite the higher market share sees less web usage (of the 20-80 scale), probably because more of them are sold to less tech-savvy users.