Optimizing Images On The World's Top 100 Websites

The world’s most visited websites receive insane amounts of traffic and push petabytes of data to visitors all around the globe. Because images alone represent over 60% of today’s Internet traffic, one would think that the top 100 websites would keep their images as light as possible. At the end of the day, saving millions of dollars in yearly bandwidth and storage fees seems like a good strategy. Let’s find out how well visual content is treated on these websites.


The only 100% reliable way to fetch all images from those websites is by using a real browser on a desktop machine. That’s why we’ve manually crawled websites in this test and exported all network activity as HAR files. While Puppeteer with stealth plugin and an auto-rotating proxy seems to produce acceptable results for the majority of use cases, we wanted to be absolutely sure we’re getting all visuals. Test results are only as good as the input data used to compute them.

Collected HAR files were loaded to and parsed in our test application. We then extracted all requests with a matching image/* mime type and discarded those with body length less than 100 bytes as those were mainly 1x1 GIF tracking pixels.

One of the major benefits of recording and using HAR files is that all binary responses are already base64-encoded right into them so we only had to load them into temporary buffers and save the binaries to disk:

(async () => {
    const src = Buffer.from(response.content.text, "base64");

    try {
        await fs.writeFile(`./sites/${site_name}/images/${file_name}`, src);
    } catch(err) {

Test results

We’ve pumped all the source images through the Optidash API. In total, we’ve collected and optimized 8353 images and saved 32.61% of the initial file size.

The actual optimization and recompression results were measured using the following formula:

100 * (original_size - optimized_size) / original_size

Image formats

JPEG is still the most commonly used image format with a 53% share followed by PNG (23%) and WebP (16%). It’s worth noting that on some websites, most notably StackOverflow, Amazon AWS, and Atlassian, SVGs are used almost exclusively.

JPEG images

  • The most commonly used (24% of all the JPEGs) encoding quality is 87 followed by 77 (8.6%) and 100 (8.3%).
  • Only 31% of JPEG images use progressive coding.
  • 4:2:0 is the most commonly used sampling scheme (69%) followed by 4:4:4 (30%) and 4:2:2 (1%)

The stats above show great potential for further reducing the file size of JPEG images. Progressive coding along with 4:2:0 sampling scheme and ideal Q value predicted on a per-image basis will yield enormous savings.

WebP images

Exactly 33.33% of the top 100 websites use WebP on as a primary image format. It’s good to see more developers decide to go the extra mile and ensure WebP variants of their website’s visual content. But serving WebP images is one thing and optimizing them is something they should consider. We’ve been able to further optimize all of the WebP content using a near-lossless algorithm and saw substantial savings there.

Interesting stats

  • The total weight of visual content across all 100 websites is 228.96MB.
  • The website with the largest number of images (397) is Rakuten.
  • The website with the heaviest visual content (11.1MB) is Sina.
  • The top five heaviest images were served on Sina (3.7MB), Reddit (3.6MB), IMDB (3.0MB), Office (2.8MB) and BBC (1.9MB).

Detailed results

Below we present a detailed list of the top 100 websites along with optimization results. Please reach out to us if you want to get access to the dataset used for compiling the following table.

RankSiteImagesBeforeAfterSavingsSavings %
01google.com592 kB81.8 kB10.2 kB11.12%
02youtube.com54815 kB751 kB64.2 kB7.88%
03tmall.com15415.4 MB7.99 MB7.43 MB48.16%
04qq.com37630 kB340 kB290 kB46.02%
05baidu.com2083.4 kB36.1 kB47.2 kB56.64%
06facebook.com8116 kB56.4 kB59.8 kB51.44%
07sohu.com1847.82 MB5.15 MB2.66 MB34.07%
08taobao.com1422.61 MB2.28 MB327 kB12.53%
09yahoo.com1462.84 MB2.3 MB541 kB19.05%
10amazon.com2132.84 MB2.4 MB434 kB15.31%
11jd.com1664.65 MB3.02 MB1.63 MB35.09%
12360.cn1403.77 MB2.28 MB1.48 MB39.32%
13wikipedia.org486.4 kB83.9 kB2.45 kB2.84% kB114 kB47.9 kB29.61%
15weibo.com1592.38 MB1.89 MB490 kB20.55%
16live.com484.38 MB3.95 MB427 kB9.74%
17zoom.us732.44 MB1.05 MB1.38 MB56.76%
18reddit.com1519.72 MB4.34 MB5.38 MB55.38% MB5.78 MB5.28 MB47.71%
20netflix.com7603 kB480 kB124 kB20.53%
21microsoft.com23275 kB266 kB9.14 kB3.32%
22xinhuanet.com2928.35 MB3.84 MB4.51 MB54.05%
23okezone.com1321.6 MB1.44 MB165 kB10.28%
24vk.com9182 kB181 kB613 B0.34%
25office.com123.37 MB2.86 MB512 kB15.16%
26instagram.com10990 kB525 kB464 kB46.93%
27myshopify.com25.28 kB5.06 kB218 B4.13%
28csdn.net1073.83 MB1.4 MB2.43 MB63.38%
29alipay.com11699 kB448 kB251 kB35.86% MB1.23 MB209 kB14.52%
31bing.com19461 kB324 kB137 kB29.71%
32bongacams.com841.6 MB1.5 MB102 kB6.38%
33blogger.com431.5 MB1.4 MB103 kB6.88%
34twitch.tv63863 kB641 kB222 kB25.75%
35aliexpress.com1974 MB2.88 MB1.12 MB28.08% kB81.7 kB10.2 kB11.13%
37zhanqi.tv1092.65 MB1.31 MB1.33 MB50.37%
38naver.com531.56 MB904 kB656 kB42.05%
39ebay.com16227 kB146 kB81.1 kB35.69%
40tianya.cn8202 kB88.5 kB113 kB56.11%
41livejasmin.com1662.21 MB2 MB213 kB9.60% MB4.18 MB387 kB8.47%
43apple.com18358 kB229 kB129 kB35.99% kB81.7 kB10.2 kB11.13%
45chaturbate.com1251.79 MB1.64 MB146 kB8.19%
46adobe.com271.01 MB746 kB259 kB25.79% MB2.91 MB3.39 MB53.80%
48amazon.in3144.91 MB4.43 MB480 kB9.77%
49tribunnews.com1511.2 MB1.03 MB171 kB14.25%
50babytree.com771.89 MB862 kB1.03 MB54.38%
51twitter.com15298 kB262 kB36.1 kB12.13%
52linkedin.com29371 kB160 kB211 kB56.77%
53msn.com1813.79 MB2.08 MB1.72 MB45.30%
54yandex.ru28273 kB207 kB65.7 kB24.08%
55sogou.com920 kB18.9 kB1.1 kB5.49%
56huanqiu.com481.22 MB745 kB480 kB39.18%
57aparat.com2459.24 MB6.16 MB3.08 MB33.38%
58yy.com1885.41 MB3.34 MB2.07 MB38.31%
59dropbox.com241.04 MB924 kB115 kB11.05%
60wordpress.com381.66 MB1.66 MB1.21 kB0.07%
61ok.ru211.88 MB1.13 MB750 kB39.91%
62pornhub.com72917 kB792 kB125 kB13.66%
63mail.ru671.02 MB664 kB356 kB34.90%
64whatsapp.com8321 kB301 kB19.3 kB6.04% kB81.7 kB10.2 kB11.13% kB81.7 kB10.2 kB11.13%
67medium.com1954.3 kB33.9 kB20.5 kB37.67%
68imdb.com534.65 MB4.62 MB26.3 kB0.57% kB26.6 kB6.6 kB19.86%
70imgur.com1535.31 MB4.46 MB848 kB15.97%
7117ok.com1657.97 MB6.29 MB1.68 MB21.13% MB1.33 MB510 kB27.76%
73cnn.com701.74 MB1.21 MB527 kB30.33%
74spotify.com45.47 kB2.26 kB3.21 kB58.66%
75indeed.com1775 B775 B0 B0.00%
76google.cn229.1 kB17.6 kB11.6 kB39.70%
77nytimes.com1316.67 MB4.35 MB2.31 MB34.70%
78xvideos.com54791 kB677 kB114 kB14.43% MB1.44 MB963 kB40.00%
801688.com2349.84 MB5.19 MB4.65 MB47.26%
81bbc.com689.7 MB7.47 MB2.22 MB22.93%
82etsy.com9349 kB276 kB72.9 kB20.92%
83mama.cn1023.32 MB1.54 MB1.78 MB53.69% MB2.45 MB749 kB23.41%
85grid.id601.15 MB924 kB225 kB19.56%
86amazon.de2263.53 MB3.04 MB488 kB13.86%
87udemy.com30522 kB436 kB85.2 kB16.33% MB4.05 MB746 kB15.55%
89flipkart.com138751 kB744 kB6.74 kB0.90%
90paypal.com15490 kB484 kB6.2 kB1.26%
91google.de592 kB81.8 kB10.2 kB11.12%
92roblox.com14695 kB593 kB102 kB14.67%
93okta.com30438 kB340 kB98.4 kB22.46%
94soundcloud.com282.7 MB2.17 MB527 kB19.53%
95pixnet.net63522 kB366 kB157 kB29.99%
96office365.com111.65 MB492 kB1.16 MB70.15%
97detik.com1314.27 MB2.16 MB2.11 MB49.45%
98booking.com591.28 MB1.12 MB162 kB12.67%
99atlassian.com49751 kB686 kB65 kB8.66%
100stackoverflow.com32181 kB139 kB42.3 kB23.34%

Ready to try Optidash?

Start optimizing your images smarter. Integrate in minutes.

Create Free Account Get In Touch

This website uses cookiesBy using Optidash, you agree to our Cookie Policy.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.