Improving performance with responsive (and responsible!) images [OpenWest]

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David Newton, St. Michael’s Hospital 1 Improving performance with responsive
(and responsible!) images OpenWest, 2015-05-07 Twitter: @newtron Github: @nwtn Email: david@davidnewton.ca Slides: https://github.com/nwtn/pres-respimg-perf-openwest

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2 Web performance

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“ 3 Many of us are fortunate to live in
high bandwidth regions, but there are still large portions of the world that do not. By keeping your client side code small and lightweight, you can literally open your product up to new markets. —Chris Zacharias, Page Weight Matters (emphasis mine)

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“ 4 Good performance is good design. —Brad Frost

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5 Why images?

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6 —Marc Andreessen, www-talk, February 1993

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“ 8 More human beings today have access to a
cellphone than…a clean toilet. –Anand Giridharadas, New York Times April 10 2010

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“ 8 More human beings today have access to a
cellphone than…a clean toilet. –Anand Giridharadas, New York Times April 10 2010

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9 — OpenSignal, Android Fragmentation Visualized (August 2014)

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10 —https://twitter.com/lukew/status/507880029737328640/photo/1

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11 img { max-width: 100%; }

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12

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13

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14 A solution: Serve one big image and let the
browser scale it

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19 Bullet 1 Bullet 2 Bullet 3

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20 Bullet 1 Bullet 2 Bullet 3

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21

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22 2x resolution = 4x as many pixels 3x resolution
= 9x as many pixels 4x resolution = 16x as many pixels

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23 more pixels = more energy more pixels = more
money more pixels = more time

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24 — Dave Rupert , Mo’ Pixels, Mo’ Problems Caption

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25 That’s why images.

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26 Responsive images

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27 A solution: Serve one big image and let the
browser scale it

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28 A better solution: Serve an appropriate image to each
user

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29

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32 SVG WebP JPEG XR JPEG 2000

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33

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34 Using JavaScript is a bad idea.

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35 Using CSS is a bad idea.

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36 http://whatwg.org/html#the-picture-element Responsive images speciﬁcation

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37 You can use this now!

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38 Firefox (Gecko) Chrome/Opera (Blink) Safari (WebKit) Internet Explorer/ Edge
srcset + sizes Works now! Firefox 38 Works now! Chrome 34 Opera 21 Works now! * Safari 6.2 Safari 7.1 iOS 8 In development picture Works now! Firefox 38 Works now! Chrome 38 Opera 25 In development Under consideration

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39 http://picturefill.responsiveimages.org/ Picturefill by Scott Jehl & others http://filamentgroup.com/lab/to-picturefill.html To
Picturefill, or not to Picturefill

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40 Resolution switching Markup

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40 Resolution switching Markup

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41 <img src="wolf4800.jpg" alt="A rad wolf" />

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42 <img src="wolf4800.jpg" alt="A rad wolf" srcset="wolf300.jpg 0.5x, wolf600.jpg 1x,
wolf1200.jpg 2x, wolf2400.jpg 3x, wolf4800.jpg 4x" />

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48 Viewport (and resolution!) switching Markup

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50 <img src="wolf4800.jpg" alt="A rad wolf" sizes="100vw" srcset="wolf300.jpg 300w, wolf600.jpg
600w, wolf1200.jpg 1200w, wolf2400.jpg 2400w, wolf4800.jpg 4800w" />

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56 <img src="wolf4800.jpg" alt="A rad wolf" sizes="600px" srcset="wolf300.jpg 300w, wolf600.jpg

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57 <img src="wolf4800.jpg" alt="A rad wolf" sizes="calc(100vw - 10em)" srcset="wolf300.jpg
300w, wolf600.jpg 600w, wolf1200.jpg 1200w, wolf2400.jpg 2400w, wolf4800.jpg 4800w" />

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58 <img src="wolf4800.jpg" alt="A rad wolf" sizes=“100%" srcset="wolf300.jpg 300w, wolf600.jpg

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59

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60 <img src="wolf4800.jpg" alt="A rad wolf" sizes="(min-width: 1000px) 33vw, (min-width:
600px) 50vw, 100vw" srcset="wolf300.jpg 300w, wolf600.jpg 600w, wolf1200.jpg 1200w, wolf2400.jpg 2400w, wolf4800.jpg 4800w" />

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62 File type switching Markup

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64 <picture> <source type="image/webp" srcset="wolf4800.webp" /> <img src="wolf4800.jpg" alt="A rad
wolf" /> </picture>

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wolf" /> </picture>

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wolf" /> </picture>

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wolf" /> </picture>

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68 <picture> <source type="image/webp" srcset="wolf4800.webp" /> <source type="image/vnd.ms-photo" srcset="wolf4800.jxr" />
<img src="wolf4800.jpg" alt="A rad wolf" /> </picture>

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69 <picture> <source type="image/webp" srcset="wolf4800.webp" /> <source type="image/vnd.ms-photo" srcset="wolf4800.jxr" />
<img src="wolf4800.jpg" alt="A rad wolf" /> </picture>

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70 Art direction Markup

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71 —Adventure Time

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72

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75 <picture> <source media="(min-width: 1000px)" srcset="wolf-crop-bg.jpg" /> <source media="(min-width: 600px)"
srcset="wolf-crop-sm.jpg" /> <img src="wolf.jpg" alt="A rad wolf" /> </picture>

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80 All the things! Markup a.k.a. the scary slide

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80 All the things! Markup a.k.a. the scary slide

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81 <picture> <source type="image/webp" media="(min-width: 1000px)" sizes="33vw" srcset="wolf-crop-big-300.jpg 300w, wolf-crop-big-600.jpg
600w, wolf-crop-big-1200.jpg 1200w, wolf-crop-big-2400.jpg 2400w, wolf-crop-big-4800.jpg 4800w" /> <source type="image/webp" media="(min-width: 600px)" sizes="50vw" srcset="wolf-crop-small-300.jpg 300w, wolf-crop-small-600.jpg 600w, wolf-crop-small-1200.jpg 1200w, wolf-crop-small-2400.jpg 2400w, wolf-crop-small-4800.jpg 4800w" /> <source type="image/webp" sizes="100vw" srcset="wolf-crop-med-300.jpg 300w, wolf-crop-med-600.jpg 600w, wolf-crop-med-1200.jpg 1200w, wolf-crop-med-2400.jpg 2400w, wolf-crop-med-4800.jpg 4800w" /> <source media="(min-width: 1000px)" sizes="33vw" srcset="wolf-crop-big-300.jpg 300w, wolf-crop-big-600.jpg 600w, wolf-crop-big-1200.jpg 1200w, wolf-crop-big-2400.jpg 2400w, wolf-crop-big-4800.jpg 4800w" /> <source media="(min-width: 600px)" sizes="50vw" srcset="wolf-crop-small-300.jpg 300w, wolf-crop-small-600.jpg 600w, wolf-crop-small-1200.jpg 1200w, wolf-crop-small-2400.jpg 2400w, wolf-crop-small-4800.jpg 4800w" /> <source sizes="100vw" srcset="wolf-crop-med-300.jpg 300w, wolf-crop-med-600.jpg 600w, wolf-crop-med-1200.jpg 1200w, wolf-crop-med-2400.jpg 2400w, wolf-crop-med-4800.jpg 4800w" /> <img src="wolf-crop-med-600.jpg" alt="A rad wolf" /> </picture>

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83 http://whatwg.org/html#the-picture-element Responsive images speciﬁcation

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84 Responsive images are a pain in the butt

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86 https://www.npmjs.com/package/grunt-respimg grunt-respimg

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87 $ npm install grunt-respimg --save-dev

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88 https://www.npmjs.com/package/grunt- responsive-images-extender/ grunt-responsive-images-extender

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89 $ npm install grunt-responsive-images- extender --save-dev

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90 https://github.com/nwtn/php-respimg/ php-respimg

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91 $ composer require nwtn/php-respimg

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92 https://wordpress.org/plugins/ricg- responsive-images/ WP RICG Responsive Images plugin

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93 Responsible images

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94 1. Responsive images

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95 1. Responsive images 2. Image optimization

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96 https://imageoptim.com/ ImageOptim https://github.com/toy/image_optim image_optim https://github.com/svg/svgo-gui SVGO-GUI https://github.com/svg/svgo SVGO

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97 SetOutputFilter DEFLATE AddOutputFilterByType DEFLATE "image/svg+xml"

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98 1. Responsive images 2. Image optimization 3. Deferred image
loading

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101 http://css-tricks.com/snippets/javascript/lazy-loading-images/ LazyLoad JS scripts and plugins, e.g.:

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loading 4. CDNs & Caching

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103 ExpiresActive on ExpiresDefault "access plus 1 month" ExpiresByType image/gif
"access plus 1 year" ExpiresByType image/jpeg "access plus 1 year" ExpiresByType image/png "access plus 1 year" ExpiresByType image/svg+xml "access plus 1 year"

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loading 4. CDNs & Caching 5. Appropriate contrast and colour

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105 7% 8% 10% 11% 29% 35% April May June
July August September

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106 7% 8% 10% 11% 29% 35% April May June
July August September

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107

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108 http://colororacle.org/ Color Oracle

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109 September 7% August 8% July 10% June 11% May
29% April 35%

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loading 4. CDNs & Caching 5. Appropriate contrast and colour 6. Text-based alternatives

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111 [alt] [aria-describedby], [aria-labelledby] [longdesc] <a> <figcaption> SVG elements and
attributes

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112 http://www.w3.org/TR/html-alt-techniques/ HTML5: Techniques for providing useful text alternatives http://www.w3.org/WAI/GL/wiki/Using_aria-describedby_to_provide_descriptions_of_images
Using aria-describedby to provide descriptions of images http://w3c.github.io/test-results/html-longdesc/cr-report.html longdesc Implementation Report http://www.paciellogroup.com/blog/2013/12/using-aria-enhance-svg-accessibility/ Using ARIA to enhance SVG accessibility http://www.w3.org/WAI/GL/wiki/Using_aria-labelledby_to_provide_a_text_alternative_for_non- text_content Using aria-labelledby to provide a text alternative for non-text content

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loading 4. CDNs & Caching 5. Appropriate contrast and colour 6. Text-based alternatives 7. Fewer images!

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114 Performance impact

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117 Unoptimized Optimized + Responsive Optimized + Responsive + Lazyload
CSS 1 KB 1 KB 1 KB HTML 2 KB 3 KB 3 KB Scripts 29 KB 33 KB 33 KB Images 661 KB 253 KB 87 KB Total 693 KB 290 KB (~58% savings) 119 KB (~83% savings)

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118 Browser Unoptimized Optimized + Responsive + Lazyload Firefox (Desktop)
2.2 s 2.0 s Safari (iOS) 2.1 s 1.7 s Average 2.2 s 1.9 s (~14% savings)

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119

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120 Accessibility Progressive enhancement Responsive web design Web performance

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David Newton, St. Michael’s Hospital 121 Improving performance with responsive
(and responsible!) images OpenWest, 2015-05-07 Twitter: @newtron Github: @nwtn Email: david@davidnewton.ca Slides: https://github.com/nwtn/pres-respimg-perf-openwest

Improving performance with responsive (and responsible!) images [OpenWest]

Improving performance with responsive (and responsible!) images [OpenWest]

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