Your Hero Images Need You! Save the Day with HTTP2 Image Loading - HighLoad++ 2016

Images are a crucial component of all websites: they evoke emotions and prompt actions. They also form 64% of website data & have the highest correlation to page load time. While modern image compression techniques can alleviate some of the negative impact of image loading, key web performance metrics such as Speed Index and Time To Interact suffer from our need for images.

With HTTP2, we have a powerful tool at our disposal to address these issues for image loading. We will explore the details of HTTP2’s multiplexing in depth and how we can leverage it to address image loading. As our images need to be optimized to maximize the benefits of image delivery over HTTP2, we will learn how to take granular control of the encoding process for progressive or interlaced images. This will directly influence the Speed Index and our users emotional response time to page visuals. To further optimize for high performance images, we will look at compatible image compression techniques.

Using HTTP2-powered high performance images will increase the perceived performance of your page, reduce load times and drive conversions.

--------------------------------------

The version of this talk was given at Highload++ 2016 conference in Moscow on 20161108.

Transcript

1. Your Hero Images Need You! Save the Day with HTTP2 Image Loading 1 / 75 — tbaldauf@akamai.com
2. Tobias Baldauf @tbaldauf tbaldauf@akamai.com 2 / 75 — tbaldauf@akamai.com
3. 3 / 75 — tbaldauf@akamai.com
4. 4 / 75 — tbaldauf@akamai.com
5. Show Images Faster Than Ever 5 / 75 — tbaldauf@akamai.com
6. Render Meaningful Content With 25% Image Data Sent 6 / 75 — tbaldauf@akamai.com
7. 7 / 75 — tbaldauf@akamai.com
8. ref. http://httparchive.org/trends.php?s=All&minlabel=Mar+15+2014&maxlabel=Mar+15+2016#bytesImg&reqImg 8 / 75 — tbaldauf@akamai.com
9. 9 / 75 — tbaldauf@akamai.com
10. What Can We Do? 10 / 75 — tbaldauf@akamai.com
11. Get compressin'! 11 / 75 — tbaldauf@akamai.com
12. Compress Aggressively 12 / 75 — tbaldauf@akamai.com
13. Ship Right Format 13 / 75 — tbaldauf@akamai.com
14. Automate Quality 14 / 75 — tbaldauf@akamai.com
15. Still a Heavy Load :( 15 / 75 — tbaldauf@akamai.com
16. We need a new form of Aggressive Delivery! 16 / 75 — tbaldauf@akamai.com
17. Enter HTTP2 17 / 75 — tbaldauf@akamai.com
18. Thanks to Clay Smith (https://twitter.com/smithclay) for this beauty! 18 / 75 — tbaldauf@akamai.com
19. kudos to my team mate Lukasz Czerpak, @lukaszczerpak 19 / 75 — tbaldauf@akamai.com
20. kudos to my team mate Lukasz Czerpak, @lukaszczerpak 20 / 75 — tbaldauf@akamai.com
21. 21 / 75 — tbaldauf@akamai.com
22. H2 Constraints 22 / 75 — tbaldauf@akamai.com
23. Ingredient #1 H2 Multiplexing 23 / 75 — tbaldauf@akamai.com
24. Progressive JPEGs 24 / 75 — tbaldauf@akamai.com
25. Sequential JPEG Progressive JPEG Images taken from http://www.pixelstech.net/article/1374757887-Use-progressive-JPEG-to-improve-user-experience 25 / 75 — tbaldauf@akamai.com
26. Scan Layers 26 / 75 — tbaldauf@akamai.com
27. Default Scan Layers Thanks to Frédéric Kayser for creating 'jsk': http://encode.ru/threads/1800-JSK-JPEG-Scan-Killer-progressive-JPEG-explained-in-slowmo 27 / 75 — tbaldauf@akamai.com
28. Org Cb Y Cr 28 / 75 — tbaldauf@akamai.com
29. 29 / 75 — tbaldauf@akamai.com
30. 30 / 75 — tbaldauf@akamai.com
31. 31 / 75 — tbaldauf@akamai.com
32. Can We Go ... Even Faster? 32 / 75 — tbaldauf@akamai.com
33. 33 / 75 — tbaldauf@akamai.com
34. 34 / 75 — tbaldauf@akamai.com
35. 1 35 / 75 — tbaldauf@akamai.com
36. 2 36 / 75 — tbaldauf@akamai.com
37. 3 37 / 75 — tbaldauf@akamai.com
38. 4 38 / 75 — tbaldauf@akamai.com
39. 5 39 / 75 — tbaldauf@akamai.com
40. Ingredient #2 Progressive JPEGs 40 / 75 — tbaldauf@akamai.com
41. How FAST Is this Mixture? 41 / 75 — tbaldauf@akamai.com
42. What defines FAST? 42 / 75 — tbaldauf@akamai.com
43. Speed Index 43 / 75 — tbaldauf@akamai.com
44. ref. Pat Meenan, http://www.slideshare.net/patrickmeenan/measuring-the-visual-experience-of-website-performance 44 / 75 — tbaldauf@akamai.com
45. ref. Pat Meenan, http://www.slideshare.net/patrickmeenan/measuring-the-visual-experience-of-website-performance 45 / 75 — tbaldauf@akamai.com
46. ref. Pat Meenan, http://www.slideshare.net/patrickmeenan/measuring-the-visual-experience-of-website-performance 46 / 75 — tbaldauf@akamai.com
47. Site A displays 7.4x faster than Site B more info at https://sites.google.com/a/webpagetest.org/docs/using-webpagetest/metrics/speed-index 47 / 75 — tbaldauf@akamai.com
48. Baseline Sequential vs. Progressive JPEGs on HTTP1.1 48 / 75 — tbaldauf@akamai.com
49. 49 / 75 — tbaldauf@akamai.com
50. 50 / 75 — tbaldauf@akamai.com
51. 51 / 75 — tbaldauf@akamai.com
52. Progressive JPEGs vs. Optimized pJPEGs on HTTP1.1 52 / 75 — tbaldauf@akamai.com
53. 53 / 75 — tbaldauf@akamai.com
54. 54 / 75 — tbaldauf@akamai.com
55. 55 / 75 — tbaldauf@akamai.com
56. Baseline Sequential vs. Progressive JPEGs on HTTP2 56 / 75 — tbaldauf@akamai.com
57. 57 / 75 — tbaldauf@akamai.com
58. 58 / 75 — tbaldauf@akamai.com
59. 59 / 75 — tbaldauf@akamai.com
60. Progressive JPEGs vs. Optimized Progressive JPEGs on HTTP2 60 / 75 — tbaldauf@akamai.com
61. 61 / 75 — tbaldauf@akamai.com
62. 62 / 75 — tbaldauf@akamai.com
63. Optimized pJPEGs on HTTP2 yield a 6% Speed Index Gain 63 / 75 — tbaldauf@akamai.com
64. What about HTTP2 Server Push? 64 / 75 — tbaldauf@akamai.com
65. // Prioritize a progressive JPEG's metadata and scan levels // with minimal 'calm' => maximum priority <img src="img/jpeg_opJPEG/tba/00001.jpg?bil=0!0"> // Create a cumulative cascade of 'calm' // for a progressive JPEG's metadata and scan levels // Each new value is added to the sum, lowering priority per scan layer <img src="img/jpeg_opJPEG/tba/00001.jpg?bil=0!100,50,20"> 65 / 75 — tbaldauf@akamai.com
66. 66 / 75 — tbaldauf@akamai.com
67. 67 / 75 — tbaldauf@akamai.com
68. 68 / 75 — tbaldauf@akamai.com
69. 69 / 75 — tbaldauf@akamai.com
70. 70 / 75 — tbaldauf@akamai.com
71. Progressive Images + HTTP2 = Win 71 / 75 — tbaldauf@akamai.com
72. Scan Layer Manipulation = Better Speed Index 72 / 75 — tbaldauf@akamai.com
73. HTTP2 Server Push + Optimized Scan Layers = Awesomesauce 73 / 75 — tbaldauf@akamai.com
74. THANKS! 74 / 75 — tbaldauf@akamai.com
75. Tobias Baldauf @tbaldauf tbaldauf@akamai.com 75 / 75 — tbaldauf@akamai.com