GThumb 4.0 Released with Major GTK4 and Libadwaita Overhaul, Bringing Modern UI and Enhanced Performance

The long-serving open-source photo manager and image viewer gThumb has reached a major milestone with the official and stable release of version 4.0. This landmark update introduces a comprehensive rewrite utilizing GTK4, Vala, and the libadwaita library, giving the classic Linux application a thoroughly modern aesthetic and significantly improved under-the-hood performance. Following its initial alpha preview earlier in the year, the stable release translates months of community testing and development into a polished experience that fundamentally transforms how the application looks and feels on modern Linux desktops.

Every facet of the gThumb interface has been meticulously redesigned to leverage the modern design paradigms offered by GTK4 and libadwaita. Long-time users will immediately notice that the application looks and behaves like an entirely new piece of software while retaining the core utility that made it a staple of the Linux desktop ecosystem for years. The transition to newer backend libraries yields immediate performance dividends, ensuring smoother interactions and tighter desktop integration. On GNOME environments, for instance, gThumb now seamlessly adopts the modern native file chooser complete with rich icon thumbnails, bridging a long-standing gap in native platform integration.

Visual breathing room is one of the most prominent improvements in the new version. By making more generous and deliberate use of padding and spacing throughout the layout, the developers have ensured that editing tools, file properties panels, and global application settings no longer feel cramped. Buttons, toolbars, and textual labels have been refined to be vastly easier to parse at a glance. Furthermore, interface ergonomics have been enhanced with the introduction of contextual overlay controls—such as zoom adjustments—which float directly over the top of images to maximize the canvas area dedicated to viewing photographs rather than chrome.

Beyond the visual refresh, gThumb 4.0 introduces several practical features to its editing suite and format support matrix. The application now incorporates a dedicated censor tool within its editing suite, allowing users to quickly obscure sensitive details in their images. Format support has also expanded significantly, with the inclusion of native playback for animated WebP and PNG images, alongside the ability to save images in the modern, highly efficient JPEG XL format. These additions ensure that the application keeps pace with contemporary web and photography standards.

Interactivity has received a massive upgrade, particularly for users utilizing modern laptop touchpads or specialized hardware. The image viewer now boasts full responsiveness to touchpad gestures, allowing users to swipe horizontally to transition smoothly between adjacent files or utilize intuitive pinch-to-zoom gestures to inspect fine details. In addition, users operating mice equipped with side navigation buttons can now utilize those physical inputs to cycle through images effortlessly, streamlining the image curation and browsing workflow.

While the release brings numerous enhancements and modernizations, it also marks a departure from some legacy functionalities. As part of the extensive codebase cleanup and architectural modernization required for the GTK4 and Vala transition, several older features have been intentionally pruned from the application. Users upgrading to version 4.0 will find that support for generating web albums has been removed, the traditional contact sheet generation feature is no longer present, and the remarkably useful duplicate file finder tool has been dropped from the feature set.

Installing gThumb 4.0 on modern Linux distributions depends largely on the chosen packaging ecosystem and the specific release cycle of the operating system. The source code for gThumb 4.0 is publicly available for compilation directly from the project’s official GitLab repository. Meanwhile, community-maintained packaging channels are working to catch up with the stable release. The unofficial Flathub listing and the corresponding unofficial Snap package on Snapcraft have not yet reflected the 4.0 release at the time of launch, though third-party maintainers have begun providing packages via dedicated Personal Package Archives tailored for distributions like Ubuntu 26.04 LTS.

For users running cutting-edge distributions, the inclusion timeline varies. Standard software repositories for distributions such as Ubuntu 26.10 do not include gThumb 4.0 out of the box, meaning that standard package manager installation commands will continue to retrieve the legacy GTK3-based iteration unless a third-party repository is explicitly utilized.

The arrival of gThumb 4.0 coincides with a broader wave of modernization washing over classic Linux photography applications. Recently, competing project Shotwell also rolled out its own GTK4 port, though it opted not to adopt libadwaita, retaining its traditional visual identity as a foundational first step toward modernizing its architecture. Concurrently, the KDE ecosystem continues to expand its multimedia software offerings with the development of a dedicated Photos application designed to serve as a modern alternative to Gwenview, highlighting a period of intense revitalization for image management software across the Linux desktop landscape.