W3C home > Mailing lists > Public > public-respimg@w3.org > May 2016

Victory laps and deep dives

From: Eric Portis <lists@ericportis.com>
Date: Tue, 10 May 2016 09:53:42 -0700
To: public-respimg@w3.org
Message-ID: <5DD0014D-EFE9-4125-AF71-614B4C259F3D@ericportis.com>
## Magick? Mitigate!

I’ll kick off with a quick PSA — if you’re using ImageMagick on a 
server *and* accept user uploads *and* haven’t heard about 
[“ImageTragick”][imagetragick], then panic, because your site is 
vulnerable to a zero-day exploit. Take steps!

[imagetragick]: https://imagetragick.com

## Have I mentioned that we did it?

I don’t “ICYMI” often. But when I do, it’s because [every 
responsive image feature is now supported by every browser][we-did-it].

The news was even better than I reported; turns out, Safari’s shipping 
`picture` implementation [*does* respond to viewport 
changes][correction-safari] and *doesn’t* double-download in the test 
case that I lazily linked to without actually, you know, checking. Yay!

Bruce “Strawman” Lawson (the man who first put the word 
“picture” between angle brackets) took a well-deserved [victory 
lap][bruce-victory-lap] over on the Opera blog, re-capping and 
reflecting on the achievement.

And our Chair, Mat Marquis, [recently appeared on the Responsive Web 
Design podcast][wilto-podcast] to discuss who, what, 
why-is-it-still-around, and what’s next for the RICG.

[wilto-podcast]: http://responsivewebdesign.com/podcast/ricg/

## It’s dangerous to go alone!

  Martin Auswöger wrote a [respimg linter][respimg-linter]! 
“Linter” doesn’t quite capture [all of the things that this little 
bookmarklet does][respimg-linter-checks], though — in addition to 
checking for syntax errors (as the ever-helpful [HTML5 
validator][valitator-nu] does), it actually loads your images across a 
full gamut of viewport sizes, and will raise the alarm if, say, your 
`sizes` is lying about the actual layout size of your image, or if it 
looks like you’re trying to kludge art-direction using `srcset`. I ran 
it across a few of my own pages, and the results were, uh, alarming. 
Bookmarklet bookmarked.

[valitator-nu]: https://checker.html5.org
[respimg-linter]: https://ausi.github.io/respimagelint/
[respimg-linter-checks]: https://ausi.github.io/respimagelint/docs.html

## Down ‘n nerdy with image formats

Colt McAnlis, developer advocate at Google, is writing [a book on image 
compression][understanding-compression] and has recently published a few 
articles on the subject, explaining how the [JPEG][colt-jpg-works] and 
[PNG][colt-png-works] compression algorithms work, and suggesting a 
plethora of tools and techniques for making [`.jpg`s][colt-jpg-smaller] 
and [`.png`s][colt-png-smaller] smaller.

If you’re game for a deep dive, these articles are well worth the 
effort. I’ll highlight one project that I discovered therein: the 
terribly-named [Butteraugli][butteraugli] image comparison tool, from 
Google. Buggerutley can provide not only a single number (like every 
other comparison metric, e.g. [PSNR][psnr] or [SSIM][ssim]), but also a 
*spatial map of dissimilarity* (woah?). Awesomely, Botticelli was 
motivated by a deep study of the biology of vision. How many engineers 
can casually drop references to the “frequency space inhibition of 
ganglion cells”?

And over on the Cloudinary blog, Jon Sneyers (creator of the 
new-and-exciting [FLIF image format][flif], which, hey!, he just gave 
[an excellent interview about][jon-interview]) takes a similarly 
technical tour of the JPEG compression algorithm and makes a wonderfully 
accessible analogy: [“JPEG is like a 
Photocopier”][jpeg-photocopier]. Recompression is bad; when you copy a 
copy of a copy, things can start to get, well, buttugli.

[butteraugli]: https://github.com/google/butteraugli
[ssim]: https://en.wikipedia.org/wiki/Structural_similarity
[psnr]: https://en.wikipedia.org/wiki/Peak_signal-to-noise_ratio
[flif]: http://flif.info

## Grab Bag

- [Google is going to funnel all of its web platform feature development 
through our sister org, the WICG][google-wicg]. In other words, 
henceforth, when Google wants to change something about web standards, 
they will be doing it via a process and community that is open to 
anyone, everywhere, at the [click of a button][click-of-a-button].
- New-axis-of-respimg-adaptation alert! It’s time to [start thinking 
about color gamuts][color-gamuts].
- [Intersection Observers][intersection-observer] will power the 
lazyloaders of the future; the feature [just landed in Chrome 
- Speaking of lazy loading, my favorite lazyloader is 
[`lazysizes.js`][lazysizes] (because it keeps the 
presentation-separate-from-markup dream alive); the imgix folks just 
wrote about [how to use `lazysizes` in conjunction with their image 
hosting and resizing service][imgix-lazysizes].
- Speaking of imgix, Oliver Pattison [wrote up his 
strategy][imgix-jekyll] for building low-overhead respimg-equipped sites 
using imgix and Jekyll.
- Ever wonder [how to decorate an `object-fit` 
- Neat: [Facebook is automatically authoring `alt` text on user 
uploads][automatic-alt] using artificial intelligence.
- [Performance matters][ft-perf].

[lazysizes]: https://github.com/aFarkas/lazysizes
[decorate-object-fit]: http://fvsch.com/code/object-fit-decoration/
[ft-perf]: http://engineroom.ft.com/2016/04/04/a-faster-ft-com/

See you in a few weeks!
Received on Tuesday, 10 May 2016 16:56:22 UTC

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