SageThumbs 2K is a modern Windows 11 shell extension written in Rust that provides thumbnails for over 326 file types not previewable by default in File Explorer. Designed to be crash-isolated and optimized for performance, it supports formats like camera RAW, HEIC/AVIF, Photoshop, DjVu, ebooks, video frames, and 3D-print files.
Key Features:
Thumbnail Support: Displays previews for 326 file types, including camera RAW, HEIC/AVIF, PSD, GIMP XCF, DICOM, OpenEXR, and more.
Right-Click Toolkit: Offers tools like convert, resize, rotate, OCR, metadata strip, combine-to-PDF/CBZ, and lossless image operations.
Quick Look Preview: Press Space to view files in a full-size popup with video/audio playback, syntax-highlighted code, and multi-page PDF navigation.
Crash Isolation: Runs out-of-process with panic guards to prevent File Explorer crashes from corrupted or malicious files.
Winget Installation: Available via the Windows Package Manager for easy deployment using the winget command line.
Target Audience and Benefits:
Ideal for graphic designers, photographers, developers, and anyone who needs seamless file preview and manipulation in Windows. SageThumbs 2K increases productivity by providing instant access to file previews and tools directly from File Explorer.
README
SageThumbs 2K
Thumbnails for everything Windows won't show you.
A modern, crash-isolated Rust shell extension for Windows 11: the clean-room revival of the legendary (but decade-abandoned) SageThumbs.
🖼️ Explorer thumbnails for 327 file types it ignores: camera RAW, Photoshop, HEIC/AVIF, video (MKV, WebM, MP4, MOV…), JPEG-XR, MS Office, DjVu, ebooks & comics, 3D-print files, and the obscure long tail.
🛡️ : runs out-of-process, panic-guarded, with a sandboxed decoder.
⚡ Fast even on big files: camera RAW thumbnails from its embedded preview instead of a slow demosaic (3–13× quicker), and no format is allowed to hang a folder.
🧰 Right-click toolkit: convert, resize, lossless rotate, combine-to-PDF/CBZ, system-wide eyedropper, OCR, and more; all non-destructive, and multi-file jobs run in parallel across every core.
👁️ Press Space to preview any file, QuickLook-style: an instant full-size popup with video & audio playback, syntax-highlighted code, rendered Markdown, multi-page PDF paging, font specimens, archive listings, arrow-key folder browsing and full-screen (F11).
🔤 Copy text off your screen: drag a region and the words land on your clipboard, in an editable window so you can fix a misread. Uses Windows' own recognizer, so it adds nothing to the download.
🎛️ Make the menu yours: drag-reorder (and show/hide) every right-click entry and its dividers; the context menu mirrors your layout exactly.
🎨 Redesigned Settings: a Win11-style category nav rail with toggle switches, system-following dark mode, 36 languages.
> I'm a huge fan of SageThumbs. There are 4 things I always install on a new build, Chrome, XnShell, Everything and SageThumbs. Having noticed multiple system crashes from SageThumbs recently and no update in almost a decade, I decided it was time to right this injustice...
>
> After about a week, and an embarrassing amount of tokens, we now have a ground-up, rust native, alternative that now supports hundreds of formats, extensive red teaming, obsessively optimized for speed with carefully audited packaging, dozens of iterations through UI/UX for simplicity, menu editors, a color picker, screenshot tool, etc.
>
> Please tell your friends, star the repo and if you find anything broken, please let me know.
The story
The original SageThumbs was a Windows legend. It made Explorer show thumbnails for hundreds of formats nothing else could. Then it stopped: no updates since ~2017, built on the proprietary, frozen GFL library.
SageThumbs 2K rebuilds it from scratch in safe Rust (a maintained decode pipeline, real crash isolation, and a native Windows 11 look) while keeping the one thing that made it great: thumbnails for everything.
✨ Features
🖼️ 327 formats
Camera RAW (Canon/Nikon/Sony/Fuji/…), PSD, GIMP XCF, DICOM, OpenEXR, FITS, HEIC/AVIF, JPEG-2000/XL/XR, Targa, SGI, and more
📚 Ebooks & comics
EPUB, MOBI/AZW (Kindle), FB2, CBZ/CB7/CBR/CBT: real covers in Explorer (a native-Rust DarkThumbs port). Plain ZIP/RAR/7Z archives within the configured file-size limit get a contact-sheet thumbnail of the images inside, too
Pure-Rust, zero-GPL decode via djvu-rs; scanned books show their text
🔊 Docs & audio
PDF first page, Microsoft Office (Word/Excel/PowerPoint) & OpenDocument, and album art for MP3/FLAC/Ogg/Opus/M4A/WMA/DSF (DSD)/… (WMA/ASF and DSD/.dsf via hand-rolled parsers; lofty can't read either)
👁️ Space-bar preview
Tap Space in Explorer (or on the Desktop) for an instant QuickLook-style popup of the selected file: any supported format at full size, plus video & audio playback (with a scrubber + volume), syntax-highlighted code, GitHub-style rendered Markdown, animated GIF/APNG/WebP, multi-page PDF paging, font specimens (.ttf/.otf/.ttc), archive listings (zip/7z/rar), ←/→ folder browsing and full-screen (F11). Optionally renders local HTML in a locked-down WebView2 (scripts off, no network) when enabled. Off by default; opt in from Settings
Multi-file Convert / Resize / Rotate / Strip and Combine-to-PDF fan out across all CPU cores (6–15× faster): a tiny dependency-free scoped thread pool, no rayon bloat in the shell DLL
🎛️ Make the menu yours
The Settings "Menu items" list lets you drag-reorder every right-click entry and its group dividers: the menu mirrors your layout exactly (WYSIWYG). Tick items off to hide them, or hit Reset order for the default
🤖 CLI + MCP server
st2k.exe: thumbnail · convert · batch · rotate · ocr · pdf · … as a scriptable/AI-agent toolbox (st2k --mcp); batch parallel-processes whole folders in one process. The MCP server adds view (decode any supported format to a PNG block so an AI agent can see the file) and compress tools
📇 Details pane & columns
An IPropertyStore handler surfaces image dimensions, EXIF camera info and audio tags in Explorer's Details pane, hover tooltips, and sortable/groupable columns, for the 327 formats Windows can't read itself. Read-only and panic-isolated, like the thumbnailer
🎨 Colour management
Embedded ICC profiles and wide-gamut images (Display P3 / Adobe RGB) render in correct sRGB instead of over-saturated; AVIF/HEIC read their colr box (incl. the iPhone-HEIC CICP Display-P3 signal), and CMYK JPEGs are colour-managed through their embedded profile; pure-Rust, no C deps
🔧 Repair file associations
One button in Settings ▸ Diagnostics re-registers SageThumbs for every enabled format when another app has hijacked the thumbnails, then clears the thumbnail cache
Redesigned Settings: a Win11-style category nav rail (General · File types · Ebook/comic · Right-click menu · Screenshots · Quick action · Quick preview · Advanced · Data & Backup) with toggle switches, Common-Controls v6, system-following dark mode, 36 languages
🔤 Screen OCR
Copy text (OCR) wherever you need it: a button in the screenshot editor (or Ctrl+T), a button on the Quick preview toolbar, a one-click tray item, or a global hotkey that goes straight to drag-a-region-get-the-text. The words land on your clipboard and in an editable window, so a misread character is fixable before you paste. Small on-screen type is enlarged before it's read, which is what the in-box recognizer needs to see it at all
💬 Send feedback
A box in the About card mails a suggestion, bug report or format request straight to the developer: no GitHub account, no email address required (leave one only if you want a reply). A failed send puts your text on the clipboard so nothing is lost
🔍 True transparency
Real premultiplied-ARGB alpha: no more gray checkerboard behind transparent PNGs
🧹 One install, a whole stack gone
There's a checklist of little utilities people reinstall on every new Windows box: a thumbnail/codec pack, a converter, a color picker, a screenshot tool, an EXIF viewer. SageThumbs 2K is one shell extension (plus a single st2k.exe) that quietly does all of their jobs, with no accounts to create and no cloud service to sign into.
Instead of installing...
You already have it
A RAW/PSD/HEIC thumbnail or codec pack (MysticThumbs, FastPictureViewer, Icaros)
Thumbnails for 327 formats, crash-isolated so a corrupt file can't hang Explorer
A preview-pane add-on for RAW/PSD/ebook covers
A built-in large preview handler for 327 formats (reading pane and Open dialogs)
A Space-bar preview app (QuickLook, Seer)
Tap Space for an instant full-size preview, macOS-style: video plays, code is syntax-highlighted, Markdown renders, PDFs page (new)
An EXIF / metadata viewer (ExifToolGUI, Opanda IExif)
EXIF, GPS, dimensions and audio tags as sortable Explorer columns
A batch converter (XnConvert, IrfanView + plugins, ImageMagick)
Right-click Convert to ~29 formats (AVIF, JPEG XL, PSD, DDS, EXR...), batched across every core
A resizer (PowerToys Image Resizer)
Right-click Resize presets and Shrink for email
jpegtran, or IrfanView's lossless-rotate plugin
Lossless JPEG rotate / flip, zero re-encode
A color picker (PowerToys, Just Color Picker, Instant Eyedropper)
A system-wide eyedropper with a 10x loupe; Space copies #RRGGBB
A metadata scrubber (ExifCleaner, BatchPurifier)
Right-click Strip metadata (EXIF/IPTC/XMP/GPS), keeps your ICC profile
A screenshot + annotate app (ShareX, Greenshot, Snagit)
Built-in region capture with an annotation editor and quick-save
An OCR tool (Capture2Text, PowerToys Text Extractor)
Copy text (OCR) four ways: right-click a file, Ctrl+T in the screenshot editor, the Quick preview toolbar, or a one-key hotkey / tray click that goes straight to drag-a-region-get-the-text (new)
An image uploader (ShareX, Imgur apps)
Upload (copy link) to a keyless host, no account
A PDF / CBZ maker (PDF24, manual 7-Zip)
Combine into PDF or CBZ, natural-sorted
ImageMagick for scripts and AI agents
st2k.exe: a full CLI and an MCP server, so agents get an image toolbox with zero extra installs
That's a dozen-plus tools folded into one tiny download with no separate codec pack to install and every decoder isolated from Explorer. The thumbnailer runs only when Explorer asks it for a thumbnail; the background helper for the screenshot hotkey and Space-bar preview is opt-in, so a default install has nothing resident at all.
Fine print, because we'd rather undersell: a few exotic formats lean on codecs already in Windows (WIC) or the bundled ImageMagick engine rather than pure Rust; SageThumbs 2K is what wires all of it into Explorer. And several tools above (PowerToys, Snipping Tool, ShareX) are free too. The point isn't that they cost money, it's that you no longer have to assemble and run a dozen of them side by side.
⭐ Like it? Help it grow
Built in the open by one person, free for personal use, no ads, no paywall. If SageThumbs 2K earns a spot on your "install on every new PC" list, a few seconds of support goes a long way:
⭐ Star the repo: the single biggest signal that this is worth maintaining.
Full includes the ImageMagick-backed long-tail formats.
Compact skips ImageMagick → the pure-Rust + OS-codec formats only.
ARM64 ships as a separate SageThumbs2K-Setup--arm64.exe for Windows on
Arm, running natively rather than emulated. It is a full build with the same bundled
ImageMagick engine as x64, so format coverage is identical on both.
> The installer registers a classic shell extension via regsvr32 and trusts a self-signed cert for the Win11 modern menu. It's a classic extension by design (not an MSIX sandbox) because it spawns ImageMagick as a subprocess.
> First run / SmartScreen: SageThumbs 2K is source-available indie software, and the installer isn't signed with a (paid) certificate, so Windows may show a blue "Windows protected your PC" screen. That's expected for unsigned indie apps: click More info → Run anyway. Every line of the code is right here for you to inspect.
🦀 How it works
IThumbnailProvider → runs in Explorer's isolated dllhost surrogate
│ (first tier that decodes wins; SVG detected up front → resvg)
image crate → WIC (OS codecs) → ImageMagick (sandboxed child) → headerless-Targa
(safe Rust) HEIC/AVIF/RAW the obscure long tail fallback
│
▼ premultiplied-BGRA top-down DIB → Explorer (real alpha)
One DLL exposes three COM coclasses: the thumbnail provider, the modern IExplorerCommand menu, and a classic IContextMenu fallback. Settings live in HKCU\Software\SageThumbs2K.
🛠 Built like it matters
Most thumbnail handlers are a weekend hack. This one's been put through the wringer:
Crash-proof by design: a malformed file can't take down Explorer.
Zero runtime dependencies, pure memory-safe Rust core, installs clean every time.
Zero-warning linting, supply-chain audits, fuzzing, Miri, and a full test + render-regression suite gate every release.
Hardened against hostile input and scanned through VirusTotal each release.
Color-managed (ICC/wide-gamut → sRGB) and obsessively tuned for speed, size, and a native feel.
🗂 Supported formats
327 extensions across Image, RAW, Ebook/comics, Document, Audio and Video
Video: mkv/webm, mp4/m4v/mov, avi, wmv, flv, mpg/mpeg, 3gp/3g2, ts/m2ts/mts, ogv, divx, …: a representative frame (~30% in) via the OS Media Foundation codecs
(PostScript without an embedded raster preview and font-only ImageMagick coders are excluded for safety; PDF uses the in-box OS renderer. Video frames come from Windows' own Media Foundation codecs; formats Windows has no codec for, e.g. FLV or MPEG-1/2 without the optional pack, keep their default icon.)
🔧 Build from source
Requires the MSVC Rust toolchain, VS Build Tools (Desktop C++), and (for the installer) Inno Setup.
> ARM64 cross-builds additionally need the ARM64 MSVC C++ tools installed through Visual
> Studio Build Tools. The ARM64 release path produces a separately named
> installer; it is not a replacement for the x64 Full build.
> scripts\build-release.ps1 always sets crt-static itself, so a release build is
> reproducible from a fresh clone either way, but a plain cargo build --release
> without it links the DLL against the MSVC CRT dynamically, which can fail
> regsvr32/DllRegisterServer with 0x8007007E (ERROR_MOD_NOT_FOUND) on a machine
> missing the VC++ Redistributable. Set the flag yourself (as above) if you're building
> the DLL directly rather than through the release pipeline.
SageThumbs 2K is a clean-room rewrite, not a derivative of the GPLv2 C++ original, and it uses no GFL. Every decoder is pure-Rust or an OS codec (RAR/CBR comics use the pure-Rust rars crate, no proprietary UnRAR), so the project's own code is entirely original and its dependencies are permissively licensed, which is what lets us license it as we choose. The optional bundled ImageMagick (for the exotic long tail) ships under its own permissive license and runs only as a sandboxed subprocess.
🙏 Credits
A from-scratch successor to Nikolay Raspopov's original SageThumbs (2004–2017, GPLv2, now unmaintained), rebuilt clean-room in Rust, with our thanks for the classic that inspired it. Built on image-rs, resvg, windows-rs, djvu-rs, and ImageMagick.
With thanks to the projects that shaped specific features:
DarkThumbs: the model for the ebook & comic cover thumbnails (EPUB / MOBI / FB2 / CBZ…).
Flameshot: inspiration for the screenshot capture + annotation flow.
XnShell / XnView: inspiration for the right-click image toolkit and shell-menu UX.
Calibre: reference for ebook formats and cover extraction.
Made with 🦀 for people who have too many weird files.
