Your Hero Images Need You! Save the Day with HTTP2 Image Loading

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.

Transcript

1. Your Hero Images Need You! Save the Day with HTTP2 Image Loading 1 / 44
2. Tobias Baldauf tbaldauf@akamai.com @tbaldauf 2 / 44
3. Improve Speed Index by 6% On Top of Best Practices 3 / 44
4. Impress With Only 15% Image Data Sent 4 / 44
5. ... With This One Weird Trick! 5 / 44
6. ref. http://httparchive.org/trends.php?s=All&minlabel=Mar+15+2014&maxlabel=Mar+15+2016#bytesImg&reqImg 6 / 44
7. Enter HTTP2 7 / 44
8. Thanks to Clay Smith (https://twitter.com/smithclay) for this beauty! 8 / 44
9. 9 / 44
10. Ingredient #1 Multiplexing 10 / 44
11. There's Another Ingredient! 11 / 44
12. 12 / 44
13. Sequential JPEG Progressive JPEG Images taken from http://www.pixelstech.net/article/1374757887-Use-progressive-JPEG-to-improve-user-experience 13 / 44
14. Scans 14 / 44
15. Default Scan Levels Thanks to Frédéric Kayser for creating 'jsk': http://encode.ru/threads/1800-JSK-JPEG-Scan-Killer-progressive-JPEG-explained-in-slowmo 15 / 44
16. 16 / 44
17. 17 / 44
18. 18 / 44
19. 1st Scan Layer Has Small Byte Size Ships Fast & Shows Soon 19 / 44
20. Ingredient #2 Progressive JPEGs 20 / 44
21. How Fast Is It? 21 / 44
22. 22 / 44
23. 23 / 44
24. 24 / 44
25. Sequential JPEGs vs. Progressive JPEGs on HTTP2 25 / 44
26. 26 / 44
27. 27 / 44
28. 28 / 44
29. Can We Go ... Even Faster? 29 / 44
30. 30 / 44
31. 31 / 44
32. 1 32 / 44
33. 2 33 / 44
34. 3 34 / 44
35. 4 35 / 44
36. 5 36 / 44
37. 37 / 44
38. 38 / 44
39. Optimized Progressive JPEGs yield 6% Speed Index Gain 39 / 44
40. 40 / 44
41. Ingredient #1: HTTP2 Ingredient #2: Progressive JPEG Ingredient #3: Optimal Scan Levels 41 / 44
42. It Will Start Image Rendering With 15% Data Sent 42 / 44
43. And Reduce Speed Index by 57% (6% via JPEG Scan Layer Optimization alone) 43 / 44
44. THANKS! Tobias Baldauf tbaldauf@akamai.com @tbaldauf 44 / 44