Firefox 156 Cuts Large-JPEG Memory Use, Speeds PDF Viewer, Adds AI Controls

The JPEG change relies on libjpeg-turbo's IDCT scaling to reduce images during decoding, rather than loading a full-size image into memory and then shrinking it. Benchmarks cited in the bug report show up to 20 times less memory used during very large image loading and decoding up to twice as fast. Because image speeds were already fast, users are unlikely to see a perceptible difference; the benefit is mainly behind-the-scenes efficiency.

The built-in PDF viewer starts up to 45 percent faster in Firefox 156. The browser now loads the background PDF.js worker sooner instead of launching it only when needed, according to the blog OMG Ubuntu. The rest of the release is primarily bug fixes.

Sponsored suggestions in the address bar are now live for users in France, Germany and Italy, with examples such as Ouais! and Juhu!. These suggestions had already been available in some other locales. Users who do not want them can disable them through Settings > Search > Firefox Suggest > Suggestions from Sponsors.

Firefox 157 is expected in about two weeks. PC World reports that the update should add support for JPEG XL, or JXL, a modern image format that offers the same quality as JPEG at a significantly smaller size. JPEG XL launched in 2021, but Safari is the only browser to support it so far. Chrome also supported it for a short period, but that ended in 2022.

A recent Firefox blog post said the browser supports whatever level of AI engagement "is right for you... Because the only person telling you how much AI you need should be you." Mozilla said opting out of current and upcoming AI features should not require endless navigation through multiple settings pages. Firefox therefore offers an AI controls section within its General Settings panel, described as a single, easily located place to block current and future AI features and related pop-ups with a toggle.

For users who want some but not all AI features, Mozilla says capabilities such as AI translations, image alt text in the Firefox PDF viewer, tab group suggestions, and key points in link previews can be individually switched on and off. Smart Window, described as Firefox's most integrated AI experience, is a new window type that has been tested in beta. Mozilla says it uses only the context a user shares with it, and that its built-in assistant can, when permitted, work directly with open tabs and browsing history to compare information, generate recommendations, summarize pages, and plan projects without requiring the user to re-enter context for every prompt. For users who want to block Google's AI Overviews, Firefox points to more than 100 extensions.

Editor's Summary Firefox 156 delivers faster PDF viewer startup, lower memory and CPU use for large JPEGs, sponsored address-bar suggestions in France, Germany and Italy, and a centralized AI controls panel. Mozilla is also preparing Firefox 157, which PC World reports should add JPEG XL support. The release reflects Mozilla's effort to combine browser performance work with granular AI opt-in and opt-out choices.