3. © 1998 PhotoSpin

4. Average page is 1795 KB
in size and growing

5. WordPress sites are worse

6. In Finland: WordPress sites
average 2,5 MB

8. Page size matters

9. Page size
does not matter
(that much)

10. Page size
≠
page performance

11. Page performance
≠
server-side performance

12. PRACTICAL TIPS

14. Optimize images

15. Optimize images for
users automatically

16. Never use the original sizes
of uploaded images

17. Prevent users using
the full size image

18. There is a filter for that
function h1_remove_full_image_size( $sizes ) {
unset( $sizes['full'] );
return $sizes;
}
add_filter( 'image_size_names_choose',
'h1_remove_full_image_size' );

19. Don’t load images
a.k.a. lazy loading

20. Make browsers
cache resources

21. Minimize,
combine,
compress

22. Minimize,
combine,
compress

23. Minimize,
combine,
compress

24. Minimize,
combine,
compress

25. Advanced stuff

26. Move scripts
to bottom

27. …with WP Simple
Asset Optimizer

28. Moving scripts
add_filter( 'wpsao_move', function () {
return array(
'jquery_json',
'gform_placeholder',
'gform_gravityforms',
'optin-monster-api-script',
'wp-mediaelement',
'visualizer-google-jsapi',
'visualizer-render'
);
} );

29. Inline CSS and
JavaScript

30. Inlining
add_filter( 'wpsao_inline', function () {
return array(
'modernizr',
'h1-stylesheet' => array(
'replace' => '../../',
'with' => get_template_directory_uri() .
'/assets/'
)
);
} );

31. Topics skipped: CDNs, responsive and retina
images, continuous performance measurement,
inlining images, CSS sprites, server side
optimization, prioritizing visible content, avoiding
redirects, DNS, asynchronous JavaScript, HTTP2…

32. Thanks!
@akibjorklund
Go to akibjorklund.com/wcfi2015
to get all the links mentioned in this talk.