Chrome 155 (stable 6 Oct 2026): JPEG XL, margin-trim, and what site owners should check

Chrome 155 is scheduled to reach the Stable channel on Tuesday, October 6, 2026, two weeks after Chrome 154. Its headline change for anyone who runs a website is that Chrome can now decode JPEG XL images. ShopperCove did not install Chrome 155 and did not run any test page in it. Everything below comes from Google’s own pages, read on 5 October 2026: the Chrome 155 release notes on ChromeStatus, the Chrome 155 beta post on Chrome for Developers, the Chromium release schedule, and the Chrome Releases blog. This is a look ahead at the feature release, not a security write-up.

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Related links

• https://www.shoppercove.com/blog/chrome-154-0-8037-97-security-update-october-2026
• https://www.shoppercove.com/blog/firefox-157-security-fixes-css-changes-october-2026
• https://www.shoppercove.com/blog/chrome-devtools-ai-assistance-gemini-guide-2026

When Chrome 155 arrives

Google’s Chromium schedule data for milestone 155 gives these dates:

• Early stable (desktop): September 23, 2026
• Stable: October 6, 2026
• First stable refresh: October 13, 2026

The same schedule data puts Chrome 154’s stable date at September 22 and Chrome 156’s at October 20. That is a two-week gap each time, counted by ShopperCove from those three dates.

“Early stable” means a small group gets the release first. On September 30, the Chrome Releases blog said the Stable channel had been updated to 155.0.8059.26/.27 for Windows and Mac “as part of our early stable release to a small percentage of users.” PiunikaWeb reported on 1 October that Chrome 155 was already on the stable channel for iPhone and iPad, while desktop and Android were still in early stable.

So some of your visitors may already be on Chrome 155. Most desktop users should get it over the days after October 6.

What the release notes list

ShopperCove counted the features that ChromeStatus lists for milestone 155: 11 enabled by default and 5 in developer trial behind a flag, with none listed as deprecated or removed. The count comes from ChromeStatus’s feature data for milestone 155, read on 5 October.

The 11 enabled by default, as ChromeStatus names them:

• JPEG XL decoding support (image/jxl)
• CSS symbols()
• CSS text-decoration-skip-spaces
• margin-trim
• Pause media playback on not-visible iframes
• Import Text (text modules)
• Additional Windowing Controls
• Algorithm updates in WebCrypto
• Digital Credentials API (issuance support)
• srgb-linear and display-p3-linear canvas color spaces
• Host and screenshot restrictions for the chrome.debugger extension API

The 5 behind a flag are WebGPU atomic-vec2u-min-max and four WebTransport items (a datagram readable stream type, datagram writable streams with prioritization, reliability attributes, and WebTransportReceiveStream). Do not build anything visitors depend on around those yet.

JPEG XL: what changes for images

ChromeStatus says Chrome 155 adds decoding of JPEG XL (image/jxl) images in Blink, using jxl-rs, which it describes as a memory-safe decoder written in Rust. It describes JPEG XL as an image format standardized as ISO/IEC 18181, with progressive decoding for faster perceived loading, wide color gamut, HDR, high bit depth, and animation.

What that means in practice:

• This is decoding. Chrome 155 can display JPEG XL files. Nothing in the notes says your images change on their own.
• Keep a fallback. These notes only cover Chrome. If you try JPEG XL, offer it as one <source type="image/jxl"> inside a <picture> element, with your current JPEG, PNG, or WebP image as the fallback <img>.
• Check your stack first. Your CDN, image plugin, or ecommerce platform has to produce and serve .jxl files with the right content type. That is outside Chrome’s notes, so check with your provider.
• Measure before switching. ShopperCove has not compared file sizes or load times. Test on your own product images before changing anything site-wide.

CSS changes you can use on content pages

margin-trim. ChromeStatus says this property lets a container drop the margin before its first child or after its last child. It works on regular block containers and multi-column containers. The notes say an earlier version of the spec also covered flex and grid containers, and that this was removed. So it will not help inside flex or grid layouts.

text-decoration-skip-spaces. This controls whether underlines, overlines, and line-throughs skip whitespace characters. It is a small polish item for link underlines and struck-through prices.

symbols(). This lets you define a list-marker style inline, for example in list-style-type, without first writing a named @counter-style rule. It supports cyclic, numeric, alphabetic, symbolic, and fixed counting systems.

As with any new CSS, older browsers will ignore what they do not understand. Write it so the page still looks fine without it.

Embeds, scripts, and extensions

Hidden iframe audio. A new media-playback-while-not-visible permission policy lets an embedding page control audible media in iframes that are hidden, meaning display: none, visibility: hidden, or zero width or height. While hidden, audible playback attempts are blocked, and the block lifts when the frame is shown again. If your product pages hide video embeds in tabs, accordions, or carousels, this gives you a browser-level way to stop hidden audio.

Text modules. JavaScript can now load a file as a string with import … with { type: "text" }, according to ChromeStatus.

WebCrypto. New algorithms in the Web Cryptography API: ML-KEM (768, 1024), ML-DSA (44, 65, 87), ChaCha20-Poly1305, and X-Wing. Most stores will not touch these directly. They matter if you build your own client-side crypto.

Digital Credentials issuance. An issuing site, such as a university, government agency, or bank, can start putting a digital credential into a user’s mobile wallet app. On Android this uses Credential Manager. On desktop it uses cross-device approaches based on the CTAP protocol.

Windowing controls. Web apps with the window-management permission can call maximize(), minimize(), restore(), and setResizable(). New CSS media features, display-state and resizable, let pages adapt to those window states.

Extensions. If you ship a Chrome extension that uses chrome.debugger, attaching can now fail on managed browsers when enterprise host or screenshot policies block it. ChromeStatus lists the errors “Host access is restricted by policy” and “Screenshot capture is restricted by policy,” and suggests handling the rejection or using chrome.scripting or chrome.declarativeNetRequest instead.

Items in the beta post that are not in the release notes

The Chrome 155 beta post, published September 16, also describes CSS corner shorthand properties, retrying failed module loads (so a second import() can succeed after a network failure), new HTML insertion and streaming methods such as streamAppendHTML(), and custom request and response headers for WebTransport.

None of those four appear in ChromeStatus’s Chrome 155 release notes as read on 5 October. ShopperCove cannot tell from these pages whether they were moved to a later release or are simply missing from one page. Treat them as unconfirmed for Chrome 155 stable until Google’s stable-day notes say otherwise.

What to do this week

1. Update Chrome after October 6. Make sure staff machines move to Chrome 155 once it reaches them. Google’s stable-day post on the Chrome Releases blog is where any security fix list will appear. As of 5 October there was no Chrome 155 desktop stable post, only the early-stable one.
2. Test product images. If you plan to try JPEG XL, set up a <picture> fallback first and check the result in Chrome 155 and at least one other browser.
3. Check hidden embeds. If you use video in tabs or carousels, decide whether the new iframe permission policy is useful to you.
4. Recheck extensions that call chrome.debugger on company-managed browsers.
5. Leave flagged features alone. The WebTransport and WebGPU items above are developer trials.
6. Plan for Chrome 156 on October 20, per the Chromium schedule.

This is a separate release from Firefox 157 and from the Chrome 154 security update linked above. Updating one browser does not update the other.