SageThumbs 2K logo, an eye with a teal spiral iris SageThumbs2K
Download

Thumbnails for hundreds of formats Windows can't read.

A fast, crash-isolated shell extension that renders camera RAW, PSD, HEIC, video, ebooks and comics right in File Explorer.

DownloadWindows 11 & 10 · 64-bit View source

Free and source-available · Windows 11 & 10 64-bit ARM64

Canon raw photo of red poppies in a field, rendered as a thumbnail
CR2
A classic portrait painting decoded from an Apple HEIC file
HEIC
A representative frame from an MKV video of a beach
MKV
Cover art of Earth from space, pulled from an EPUB ebook
EPUB
A layered Photoshop PSD design file with a colour palette and artwork
PSD
The Great Wave artwork shown as a CBZ comic cover
CBZ
Nikon raw portrait of a child, rendered as a thumbnail
NEF
A flat vector illustration of pyramids at sunset from an SVG file
SVG
Starry Night album artwork embedded in a FLAC audio file
FLAC
A high dynamic range mountain landscape from an OpenEXR file
EXR
Sony raw architectural photo of a brick building
ARW
A representative frame from an MP4 video of a forest path
MP4
Sunflowers painting decoded from a GIMP XCF file
XCF
Fujifilm raw photo of a misty winter lake
RAF
hundreds of formats, 8 categories

The long tail of formats, all in one extension.

Windows covers a few types. The rest is content-sniffed and routed to a Rust decoder, a Windows codec, or an isolated converter.

Image 213

155 are a full decode of the image itself; 58 ride the file's own embedded/carried preview instead of a full decode. .avci, .heic, .heics, .heif, .heifs, .hif additionally need the OS's WIC HEIF codec. .avif additionally needs the AV1 Video Extension. .hdp, .jxr, .wdp, .wmp additionally need the OS's WIC JPEG XR codec.

.3dm .3mf .af .afdesign .afphoto .afpub .aftemplate .ai .apk .apkm .apks .apng .ase .aseprite .avci .avif .bgcode .blend .blend1 .blend10 .blend11 .blend12 .blend13 .blend14 .blend15 .blend16 .blend17 .blend18 .blend19 .blend2 .blend20 .blend21 .blend22 .blend23 .blend24 .blend25 .blend26 .blend27 .blend28 .blend29 .blend3 .blend30 .blend31 .blend32 .blend4 .blend5 .blend6 .blend7 .blend8 .blend9 .bmp .bw .c4d .cal .cals .cdr .cdt .cin .clip .cmx .cur .cut .cxr .dcm .dcx .dds .dib .dicom .dpx .dwg .dxt1 .dxt5 .emf .emg .emz .eps .exr .f3d .farbfeld .fcstd .ff .fits .fl32 .fts .gco .gcode .gif .hdp .hdr .hdri .heic .heics .heif .heifs .hif .icb .icns .ico .icon .iff .ilbm .j2c .j2k .jfif .jng .jnx .jp2 .jpc .jpe .jpeg .jpf .jpg .jpm .jps .jpx .jxl .jxr .kra .lbm .livp .mac .mat .max .mcaddon .mcpack .mctemplate .mcworld .miff .mng .mpo .obj .ora .pam .pbm .pcd .pcx .pdb .pdd .pdn .pfm .pgm .pgx .ph .phm .pix .ply .png .pnm .ppm .procreate .psb .psd .psdt .psp .pspbrush .pspframe .pspimage .pspmask .pspselection .pspshape .psptube .ptif .pwp .pxo .qoi .ras .rgbe .rla .rle .rmf .scr .sct .sf3 .sfw .sgi .skb .sketch .skp .sldasm .slddrw .sldprt .spla .sti .stl .sun .svg .svgz .tga .tif .tiff .tiff64 .tim .tm2 .tpic .tub .vda .vicar .viff .vips .vst .wdp .webp .wmf .wmp .wmz .wpg .xapk .xbm .xcf .xd .xpm .xv .xyze

Document 43

Each thumbnail is the format's own cover image, or its first page rendered.

.djv .djvu .doc .docm .docx .dot .dotm .dotx .ggb .indd .indt .key .numbers .odf .odg .odp .ods .odt .otp .ots .ott .pages .pdf .pot .potm .potx .pps .ppsm .ppsx .ppt .pptm .pptx .pub .vsd .vsdm .vsdx .xls .xlsb .xlsm .xlsx .xlt .xltm .xltx

Camera RAW 34

Each thumbnail rides the file's embedded preview, with a full demosaic as the backstop when there isn't one.

.3fr .arw .bay .cap .cr2 .cr3 .crw .dcr .dcs .dng .drf .erf .fff .iiq .k25 .kdc .mdc .mef .mos .mrw .nef .nrw .orf .ori .pef .ptx .pxn .raf .rw2 .rwl .sr2 .srf .srw .x3f

Video 26

Each thumbnail is a representative frame grabbed from the video. .3g2, .3gp, .asf, .avi, .divx, .f4v, .m2ts, .m4v, .mkv, .mov, .mp4, .mts, .ogv, .qt, .ts, .webm, .wmv additionally need the OS Media Foundation codecs.

.3g2 .3gp .asf .avi .divx .f4v .flv .m1v .m2p .m2ts .m2v .m4v .mkv .mov .mp2v .mp4 .mpeg .mpg .mpv .mts .ogv .qt .ts .vob .webm .wmv

Audio 18

Each thumbnail is the file's embedded cover art (a waveform when there is none and the format is uncompressed PCM).

.aac .aif .aifc .aiff .ape .dsf .flac .m4a .m4b .mp3 .mpc .oga .ogg .opus .spx .wav .wma .wv

Ebook & comics 12

Each thumbnail is the format's own cover image, or its first page rendered.

.azw .azw3 .cb7 .cbr .cbt .cbz .epub .fb2 .fbz .mobi .phz .prc

Archive 3

Each thumbnail shows the images found inside the archive, not one photo.

.7z .rar .zip

Preview only Space

No thumbnail for these, but press Space on one and it opens in the Quick preview, rendered.

.eml .msg .db .sqlite .sqlite3 .csv .tsv .ipynb .md .html .url code fonts
No app to open

It lives inside File Explorer.

Thumbnails appear as files land. Right-click any supported file for the toolkit; Settings decides what gets hooked.

Folders that show their contents

RAW shoots, renders, icons and documents preview in the grid instead of a wall of blank icons.

  • Generated on demand, the moment a file appears
  • Cached by Windows, so the second look is instant
  • Read-only, and nothing leaves your machine
A Windows 11 File Explorer window filled with colourful thumbnails generated by SageThumbs 2K

A right-click toolkit

Convert, resize, rotate, watermark, combine to PDF or CBZ, OCR, colour-pick, rename, set as wallpaper. Nothing leaves your machine.

ConvertResizeRotateWatermarkCombine to PDFRename by patternOCREyedropper
The SageThumbs 2K right-click context menu in Windows Explorer

You decide what hooks

A dark Settings panel: toggle any type, cap size and quality, reorder the right-click menu. In 36 languages.

The SageThumbs 2K Settings window cycling its category tabs: a Win11-style nav rail, toggle switches, and system-following dark mode

Convert anything, in bulk

Right-click, Convert… to JPG, PNG, WebP, TIFF and more. Batches run in parallel; originals are never touched.

  • Resize by fit, percentage or exact pixels
  • Per-format quality: JPEG, WebP lossless, PNG level
The SageThumbs 2K Convert dialog: output format, resize, per-format quality and output-folder options
Press Space

Tap Space. See anything.

Select a file, press Space: an instant full-size preview. The Quick Look Windows never had.

A real preview, not just a thumbnail

Anything SageThumbs can decode, plus what a still image can't do:

  • Video and audio play, with a seek bar
  • Code highlighted with line numbers; Markdown rendered, with an outline
  • PDFs scroll like a document, with page thumbnails and search
  • Archives list their contents; SQLite databases open as tables
  • Email (.eml, Outlook .msg) opens as mail: nothing fetched, nothing extracted
  • 3D-print models render shaded; one click copies the text out of any picture
Space to open or close← → flip through the folderF11 full-screenLight or dark, per windowNever steals focus
SageThumbs 2K Quick preview, opened by pressing Space in Explorer: a rendered Markdown document, an email showing its headers and attachment list, a shaded 3D-print model, and a syntax-highlighted source file, side by side

Code and text, actually readable

Source opens highlighted, in its own language. Chinese, Japanese, Korean and Thai read correctly: the encoding is detected, not assumed.

The SageThumbs 2K Quick preview showing a Rust source file with syntax highlighting, line numbers and the caption toolbar
One install, not a dozen

The whole stack it lets you delete.

A dozen little utilities people reinstall on every Windows box, done by one shell extension and one st2k.exe.

a dozen+separate tools' jobs, folded in
oneinstaller, no separate dependencies
0tray icons or background services
100%local image processing, your files stay put
Instead of
MysticThumbsFastPictureViewerIcaros
You get

Thumbnails for the formats Windows ignores, crash-isolated so a bad file can't hang Explorer.

Instead of
a preview-pane add-on
You get

A large preview handler in the reading pane and Open dialogs.

Instead of
QuickLookSeerWinQuickLook
You get

Tap Space on any file for an instant full-size preview.

Instead of
a free .msg vieweropening Outlook to read one file
You get

Space on an .eml or Outlook .msg reads the mail. Nothing fetched, nothing opened.New

Instead of
Windows 3D Viewerloading a slicer just to look
You get

STL, OBJ and PLY models get a real shaded thumbnail and preview.New

Instead of
ExifToolGUIOpanda IExif
You get

EXIF, GPS, dimensions and audio tags as Explorer columns.

Instead of
XnConvertIrfanViewImageMagick
You get

Right-click Convert to ~29 formats, batched across every core.

Instead of
PowerToys Image Resizer
You get

Right-click Resize presets and Shrink for email; never upscales.

Instead of
PowerToys Color PickerJust Color PickerInstant Eyedropper
You get

A system-wide eyedropper with a 10x loupe.

Instead of
Capture2TextPowerToys Text Extractor
You get

Copy text off your screen: drag a region, the words land on your clipboard.

Instead of
ExifCleanerBatchPurifier
You get

Strip metadata losslessly, including Content Credentials (C2PA).

Instead of
a washed-out HDR screenshot
You get

Screen capture that matches an HDR display, per monitor.

Instead of
ShareXGreenshotSnagit
You get

Region or window capture with annotations, quick-save and a delay.New

Instead of
ImageMagick for scripts / agents
You get

st2k.exe: a CLI plus an MCP server, zero extra installs.

Exotic formats lean on Windows' codecs or the bundled ImageMagick. The point is not running a dozen tools.

For power users and AI agents

A command line and an MCP server, in the box.

Everything the menu does, st2k.exe does from a terminal. It speaks MCP, so agents see RAW and PSD as images.

  • Scriptable batchThumbnail or convert whole folders in parallel.
  • OCR and PDF toolsText out of images; many pages into one PDF.
  • An agent-ready view toolA model sees a RAW, PSD or HEIC it could not open.
st2k 
# render any supported format to an image
$ st2k thumbnail photo.cr2 out.png --size 512

# batch a whole folder, in parallel
$ st2k batch thumbnail .\raw\ --size 512
  rendered 248 files

# RAW to PNG, no Photoshop needed
$ st2k convert render.psd out.png

# expose every format to an AI agent
$ st2k --mcp
  MCP server ready: view, convert, ocr ...
safety

Safe by construction, not by promise.

It runs inside explorer.exe, so the bar is high.

Memory-safe Rust

Rust, sandboxed at every Explorer boundary. A hostile file cannot crash Explorer or reach your system.

Read-only by default

Thumbnailing never writes to your files. The toolkit creates new files; it never overwrites the original.

Free and source-available

Free for personal use under PolyForm Noncommercial, full source on GitHub.

how it compares

Where SageThumbs 2K fits.

How SageThumbs 2K stacks up, honestly, against the usual suspects.

Comparison of SageThumbs 2K against the classic SageThumbs, MysticThumbs, Microsoft PowerToys and QuickLook
Tool Price RAW / PSD / HEIC thumbnails Space-bar full preview Convert / resize / OCR toolkit Maintained
SageThumbs 2K Free at home; at work US$2.99 per PC monthly or US$49 once Yes, 334 formats Yes: video, audio, code, PDFs, SQLite Yes, built in Yes, actively developed
Classic SageThumbs Free (GPL-2.0) Images only (bundled GFL) No No No, discontinued 2019
MysticThumbs Paid (14-day trial) RAW, PSD, HEIC/AVIF, audio, ebooks; no video Yes (QuickView) Convert only Yes, commercial
Microsoft PowerToys Free, open source No: SVG, PDF, Markdown and code only Yes (Peek) Some, as separate utilities Yes, active (Microsoft)
QuickLook (QL-Win) Free, open source No, preview only Yes, its whole purpose No Yes, active

Competitor details from each project's own pages, August 2026. SageThumbs 2K is a clean-room rebuild that credits Nikolay Raspopov's original.

pricing

Free at home. One licence per PC at work.

Personal use is free. Business use needs a licence for each PC: pay monthly, or once.

Personal

Free

Home, hobby, anything non-commercial.

  • Every format, every tool
  • No account, no trial, no feature gate
  • Source on GitHub

Download

Business

US$2.99per PC, per month

Cancel any time.

  • Every update while you subscribe
  • Same full app as the one-time licence

Subscribe

Volume

Quote

About 25 PCs or more.

  • One contract for every machine
  • Purchase order or bank transfer

One key per PC, emailed the moment you pay; redeem it under Settings > Licence. Prices in USD, tax added at checkout.

questions

Questions, answered.

Is it really free?
Yes, for personal use, with full source under PolyForm Noncommercial 1.0.0. Business use needs a licence per PC: US$2.99 a month, or US$49 once with 12 months of updates (US$29 for 12 more).

How do I buy a business licence?
Online, by card: US$2.99 per PC per month, or US$49 per PC once; set the quantity to your PC count. One key per PC arrives by email; paste it under Settings > Licence. Cancel the monthly plan any time at checkout.connections.icu/manage. 25 PCs or more, or a purchase order: request a quote.

Is it safe to run?
Public code, memory-safe Rust, every decode crash-isolated. A bad file can't take down Explorer.

Will it slow down Explorer?
No. Thumbnails are cached by Windows, the fast paths are pure Rust, heavy decodes run out of process, and you can cap sizes in Settings.

Does SageThumbs 2K work offline?
Yes. Everything runs locally; nothing is uploaded and no account is needed. Only the optional link-upload tool touches the network.

Why does Windows SmartScreen warn me?
3.0 and later are code-signed by LUNARWERX LLC. SmartScreen can still warn while a new publisher earns reputation: click More info, then Run anyway.

Which versions of Windows?
Windows 11 and 10, 64-bit. Both right-click menus.

Is there a version that does not need installing?
Yes, every release ships a portable zip: unzip and run, no admin rights. The preview pane, details pane and the Windows 11 modern menu need the installer.

Which formats are supported?
Hundreds; see the wall above, or run st2k formats for the live list.

Stop staring at blank icons.

Install once. Every RAW, PSD, HEIC, video and comic in your folders just shows up.

DownloadWindows 11 & 10 · 64-bit View source
Windows 64-bit Installer · .exe also portable .zip
Windows ARM64 Installer · .exe also portable .zip

v3.1.0 · all releases

Request a quote