1
At a glance the headline numbers for Image CDNs impact
Performance impact by image_cdn provider.
9
Providers ranked
After min-sites filter
27,273
Sites in sample
Combined across all items
0.02
Best CLS (p75)
Fastly Image Optimizer
The State of Web Vitals · Q2 2026 · 189,915 sites · all devices field datacorewebvitals.io/state-of-cwv
2
The ranking sorted by CLS at p75, fastest first
| # | Provider | CLS p75 | Passing | Sites | |
|---|---|---|---|---|---|
| 1 | Fastly Image Optimizer | 0.02 | 87.5% | 1,142 | |
| 2 | ImageKit | 0.05 | 80.0% | 79 | |
| 3 | Imgix | 0.05 | 86.6% | 805 | |
| 4 | Akamai Image Manager | 0.05 | 85.0% | 7,236 | |
| 5 | Bunny Image Optimizer | 0.05 | 86.1% | 17,162 | |
| 6 | Uploadcare | 0.06 | 86.2% | 92 | |
| 7 | Sirv | 0.09 | 80.0% | 57 | |
| 8 | Cloudinary | 0.14 | 71.2% | 512 | |
| 9 | Thumbor | 0.21 | 60.1% | 188 |
The State of Web Vitals · Q2 2026 · 189,915 sites · all devices field datacorewebvitals.io/state-of-cwv
3
Passing CLS per provider which group passes the CLS most often
ProviderSitesPassing CLSp75
Fastly Image Optimizer 0.6% 1,142 0.02
imgix 0.4% 805 0.05
Uploadcare 0% 92 0.06
Bunny Image Optimizer 9% 17,162 0.05
Akamai Image Manager 3.8% 7,236 0.05
ImageKit 0% 79 0.05
Sirv 0% 57 0.09
Cloudinary 0.3% 512 0.14
Thumbor 0.1% 188 0.21
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good CLS (0.1 at p75) · one value per site
87% of Fastly Image Optimizer sites pass CLS. Thumbor trails 27 points behind, leaving 40% of its sites failing. computed
The State of Web Vitals · Q2 2026 · 189,915 sites · all devices field datacorewebvitals.io/state-of-cwv
4
All five vitals at once the whole category without toggling - cell is the pass rate, small number the p75
LCP
INP
CLS
FCP
TTFB
ImageKit 0%
673.1s
84148ms
800.05
682.0s
501.2s
Sirv 0%
762.5s
96111ms
800.09
652.2s
431.5s
Akamai Image Manager 3.8%
812.2s
95116ms
850.05
771.7s
571.2s
Bunny Image Optimizer 9%
822.2s
96113ms
860.05
761.7s
591.2s
imgix 0.4%
862.0s
91136ms
870.05
851.5s
75821ms
Thumbor 0.1%
842.2s
95133ms
600.21
841.6s
65960ms
Fastly Image Optimizer 0.6%
881.7s
93118ms
870.02
911.2s
81720ms
Uploadcare 0%
882.0s
88154ms
860.06
871.4s
82701ms
Cloudinary 0.3%
792.4s
76183ms
710.14
761.8s
591.1s
60%95%+ passing Cell: pass rate, small number = p75 · faded rows: under 100 sites
One row per provider, one column per vital - the cell is the share of sites passing, the small number the p75. No toggling needed to see where the category actually differs.
imgix leads on CLS: 87% of its sites pass. Thumbor trails at 60%. computed
The State of Web Vitals · Q2 2026 · 189,915 sites · all devices field datacorewebvitals.io/state-of-cwv
Related signals Search (6) → Font services (4) → Personalization (6) → CDN (16) → Chrome field data from 189,915 sites, representing millions of real page loads · How we measured
Chrome field data from 189,915 sites, representing millions of real page loads. How we measured.