Gyazo image links can’t be guessed

When uploading an image, Gyazo will automatically create a link containing a 32 digit ID consisting of 16 kinds of characters, 0 to 9 and A to F, like this:

This makes 34,282,366,920,938,463,463,374,607,431,768,211,456 or 16^32 possible IDs. With over 1 billion (1,000,000,000) images on Gyazo currently, if you type image IDs randomly, the probability of finding an image is  0.00000000000000000000000029%. 

Mathematically, you can see that it is very difficult to guess the correct ID of a Gyazo image. Also, since Gyazo has measures in place to prevent against DDoS attacks, it is impossible to figure out the ID through a brute force approach.

Although each image has a safe and unpredictable link, if you mistakenly sent a URL to a different party than you assumed, there is a possibility that the image will be visible by someone you don’t want to view it. When using the free version of Gyazo in the past, I heard that some accidents occurred due to this kind of mistake, and some people banned Gyazo itself.

I would like to recommend Gyazo Teams for companies to prevent such accidents.

Share interesting captures to get reactions, new followers, and increase your chance to win each month.

On the leader board for each game you can see Twitter accounts with the most reactions on their tweets with Gyazo captures each month. From this list we will select two people per game per month to win $25 gift cards and one lucky person will win up to $400 in elite gaming gear – see those details below.  

Note: We will use our own criteria to select winners. To increase your chances be sure to share high quality, interesting captures that get lots of reactions on Twitter (likes, retweets, and comments) and do your best to climb the leader board. We recommend using Gyazo GIF and Gyazo Replay to capture HD videos for maximum results.

Grab every good game moment

Save your beauty of a highlight playYou just got a vicious monster kill and naturally you want to show it off. After the heat dies down hit the hotkeys to capture and then keep playing. Later on you can review the clip and share the page or video link. 

With full HD clips even super detailed gameplay can be seen clearly.

Find out where it all went wrongSometimes you can’t understand what happened because it just happened so fast. By grabbing a quick replay you can go back and see exactly how that tough enemy got you, and you can improve next time. Gyazo Replays have good framerate so you can see even lightning-fast action.

Promote your stream while you playMaybe you’re growing your twitch following but people on twitter and discord don’t get that excited just from seeing your channel link. Use Replay to capture while you play, then share out a replay together with your link while you’re waiting to respawn or between matches. By sharing high quality clips more frequently you’ll get more followers and subscribers in no time.

Gyazo Pro Features

  • Easy access to all your captures – Search, browse, and collect
  • Password protect specific captures
  • Search text in your images and extract it with OCR scanning
  • Edit to add text, arrows, boxes, mosaic blur, stickers, and emoji
  • Easy video trimming
  • No more banner ads
  • Take 60 second screen GIF and HD video captures in Gyazo GIF
  • Take 30 second full screen HD replays in Gyazo Replay

When you’re working from home it can be too slow to show people what’s on your screen or explain with words, but Gyazo lets you share new captures in 2 seconds or less.

With Gyazo Pro you can do more and save more time with clear, fast, and professional screen capturing. It’s perfect for working from home, playing games, and studying. Use it to share instantly or take visual bookmarks for later.

About the Content-DPR header

The Content-DPR header details are now written as one of the HTTP Client Hints according to the editor’s draft of the 7th edition HTTP Client Hints specification, removed from the IETF Draft, and are in the process of being included in the HTML specification as of a few days before this article was written.

As the name suggests, this is a header that can notify the client of the DPR (Device Pixel Ratio) of the content being delivered.

Until now, when displaying an image in HTML, it was done without considering the DPR of the content itself. For example, when embedded in HTML, a screenshot taken on a Retina display would be displayed at double the original size in both the vertical and horizontal directions. Of course, screenshots uploaded to Gyazo were the same.

The solution to this problem is the Content-DPR header. If the client such as a modern browser supports them, the Content-DPR header details are acquired at the time of display and will be used to determine the appropriate size for the content. Currently the Content-DPR header is supported by Google Chrome with the naturalWidth and naturalHeight calculated and used at the time of display.

A sample is presented below. Currently, only Chrome is supported, so please look at it with Chrome.

Changes to IE11 and MS Edge support

For some time now we have informed people on our help page that we do not recommend the use of unsupported browsers, especially IE11. However, we know some people continued to use IE11 and we continued to develop support it as much as possible while making modifications as necessary.

However, we have now stopped all updates for IE11 except for vulnerabilities. The latest features and user experience are no longer supported. Also note that Microsoft has recommended migrating to Edge since 2018.

We have also discontinued development for the older versions of MS Edge with the release of the new MS Edge based on Chromium technology in January 2020. Chromium is the core browser technology behind Google Chrome, Brave, and other major browsers. 

The newer version of MS Edge is available here. 


Gyazo Extensionは日本時間の2020年5月21日〜2020年7月29日の間、Chrome Web Storeから取り下げられていましたが、Chrome Web Storeのに則る形で機能を変更することで無事再公開することが出来ました。結果的に取り下げから再公開までに次の変更をExtensionの機能に対して行いました。

  • GithubでのGyazo URL貼り付け時のMarkdown変換サポート機能の削除
  • キャプチャー後のURLのクリップボードへの自動書き込みのオプション化

Chrome Web Store側から適切なフィードバックを得られず、またCOVID-19の影響下でレビューに時間が掛かる中、結果的にExtensionの開発者である我々が手探りでポリシーと機能を検討し、変更と提出を繰り返すのは非常に大変で根気を必要とする作業でした。また、PushBulletのように各種機能を残したまま再公開出来ている事例があることについては公平ではないと感じているのが正直な感想です。Chromeは近年ユーザーも多く、また悪意のあるExtensionからユーザーを保護することは非常に重要であるということには同意しますが、その一方でExtension開発者に対してのフィードバックは非常に不親切であると感じました。もう少し分かりやすいフィードバックが行われるようになることを期待しています。


Chrome Web Store側からはに関する違反があったと2020年5月7日に通達されていました。この際、ここから14日間の間に問題を解決しない場合Chrome Web Storeから取り下げられる旨が書かれていたので、対応を開始しました。

この際、まずは現状の機能についてChrome Web Store上でPermissionの目的について記述し、いくつかコードの変更やAPIの変更などに依って不要になっているPermissionがあったので削除をしました。


ですが、これだけでは再承認を得ることが出来ず、Chrome Web Storeから送られてくるメールの内容も初めの通達と同じ文言でした。詳細に関することや具体的な違反内容について触れられていませんでした。

そうこうしている間に期限である14日が過ぎてしまい、Gyazo ExtensionはChrome Web Storeから取り下げられてしました。

このまま闇雲に変更と再申請を繰り返しても仕方ないと考え、取り下げられたという通知のメールに返信する形でGoogleのChrome Web Storeチームに対して、非公開になっている理由や解決すべき点について問い合わせを行いました。


  • ユーザーデータの取り扱いに関するMinimum Permissionに関する問題

    • (Chrome Web Storeチームからの返信メールより。原文ママ)


一方でやはりPermissionがminimumではないと捉えられているのだということを再認識したので、ここで改めて更にPermissionを削ることは果たして可能なのかについて検討しました。ここで、Chrome Web StoreのDashboard上のPrivacyタブに再度注目すると、Extensionに関する を記載する箇所の説明にこう書かれていました。


このことより、Gyazo Extensionが提供していたある機能に目を付けました。Gyazo ExtensionではGithubのissueやPull RequestのエディタにGyazoのURLを貼る際にMarkdown形式に変換する機能を提供していました。この機能がこのに反しているのではと考え、それをまずはデフォルト無効(ユーザーが任意にオプションより有効にできる)にしました。

この変更を加え再提出するも承認を得ることが出来なかったので、この機能を削除した を提出し、本日承認を得ることが出来ました。

About the Introduction of Content-DPR to Gyazo images

Gyazo is an image-sharing service that mainly handles screenshots and is the first app where you can share scale-sensitive images from a retina display and have it displayed at the right size, such as a small UI element like a navigation bar or menu item.

Recently, we were aware that many users were taking screenshots with DPR greater than 1, such as on a Mac Retina display so naturally I was wondering if the fact that those images appear unintentionally large on your screen could be avoided. To that end, we now save the DPR when the image is uploaded and use this to provide processing that controls the display size of these images on Gyazo.

However, the images uploaded to Gyazo do not only live on Gyazo but are often expanded and viewed on Scrapbox as well as many other websites, blogs, and chat apps where the final display size may change. In such cases, it is possible to use the included DPR by using HTML embed code which can be copied easily from the share menu on any Gyazo image page.

With this change the Content-DPR header can convey the correct DPR to the client, and the client can display the image at an appropriate size. I sincerely hope you enjoy sharing screenshots that can be viewed at the proper size. 

More to come

We always have asked you to use the latest browsers. While we did our best to support older browsers, sometimes this resulted in increased development costs and prevented us from providing the best experience using the latest browser features.

In light of this situation, as well as with the news from Microsoft about retiring Internet Explorer 11 and the release of the Chromium version of Microsoft Edge, we have made the decision to stop supporting these older browsers. 

We apologize for any inconvenience this may cause and ask that you please use a modern browser when using Gyazo such as Google Chrome or Mozilla Firefox. Gyazo uses the latest web browser features, including PWA

(Progressive Web App) technology for uploading through our mobile apps.

How do I record my microphone? Are there more options?

When you capture with Gyazo Replay it records any sound on your PC including any apps, music, and your microphone if you are listening to it.

To record your microphone when you capture, go to the Windows menu -> Sound -> Recording -> Microphone -> Properties -> Listen -> click “Listen to this device.” After you’re done capturing you probably will want to turn this off again so you don’t hear your own voice being played back.

To turn sound recording off for Gyazo Replay you can uncheck the box in the Gyazo settings panel. Open Gyazo settings by looking at the Windows notification area at the bottom right corner of your screen -> Right click the Gyazo icon -> More options -> Gyazo Replay -> Click the box next to “Record Audio.”

Whenever you share a Gyazo Replay with sound your viewers can adjust the volume or mute it as usual.

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