LocalPix
A free, offline image converter for macOS and Windows.
Convert between JPEG, PNG, WebP, AVIF, JPEG XL, JPEG 2000, OpenEXR, GIF, TIFF, BMP and ICO — without uploading anything.
Download the latest release →
Why LocalPix?
- It's local. Your images never leave your computer. No upload, no account, no telemetry.
- It's free and open source. Use it for personal or commercial work; no subscriptions, no watermarks.
- It's fast. Native image processing — typical conversions are done in milliseconds.
- It supports the formats you actually have. Read 13 formats including iPhone HEIC, Photoshop PSD, SVG, PDF, JPEG 2000, and OpenEXR. Write 11, including modern ones like AVIF and JPEG XL.
- It handles batches. Drop a whole folder, convert everything at once. Per-format quality controls, privacy controls, a max-file-size cap, custom output folder.
- Updates on your terms. A manual Check for updates button in the footer — one anonymous version check when you click it, never in the background.
Download
Grab the right file from the latest release:
| Platform | Download |
|---|
| macOS (Apple Silicon — M1/M2/M3/M4) | LocalPix-*-arm64.dmg |
| Windows (Intel/AMD) | LocalPix Setup *.exe |
Intel Macs and Windows ARM aren't in the default release but can be built from source — see For developers below.
Install
macOS
- Open the downloaded
.dmg.
- Drag LocalPix to your Applications folder.
- First launch: macOS will show a warning that "Apple could not verify LocalPix is free of malicious software." Pick one of these:
- Right-click (or Ctrl-click) the app → Open → Open in the next dialog. Only needed once.
- Or open System Settings → Privacy & Security, scroll to the LocalPix message at the bottom, and click Open Anyway.
This warning shows for any app that hasn't been signed with Apple's $99/year Developer ID. LocalPix is genuine — the warning is just macOS being cautious about software that hasn't paid for the certificate. After the first launch, you won't be prompted again.
Windows
- Double-click the installer (
LocalPix Setup *.exe).
- Windows may show "Windows protected your PC" via SmartScreen.
- Click More info, then Run anyway.
- The installer drops LocalPix into your user folder — no admin password needed.
Same story as the macOS warning. SmartScreen flags software that hasn't been signed with a $300+ Windows code-signing certificate. LocalPix is genuine; it just hasn't paid for the sticker.
How to use it
- Drag images into the drop zone, or click to browse.
- Pick an output format from the row of buttons (alphabetical: AVIF, BMP, GIF, ICO, JPEG, JPEG XL, PNG, TIFF, WebP).
- Tweak quality, effort, or other options if you want — defaults are sensible for everyday use.
- Click Convert on a file row or Convert All for a batch.
Converted files land in ~/Documents/LocalPix/ by default. Click Change… next to the output folder to pick somewhere else; LocalPix remembers your choice between launches.
Max file size — the slider under the drop zone caps how large a file can be added (default 250 MB, up to 2 GB or no limit). Files are held in memory while they convert, so a cap keeps one giant file from slowing down or freezing the app on machines with less RAM; anything over the cap is skipped at drop time. Hover the ? next to the label for the short version.
Checking for updates
LocalPix never checks for updates on its own — that would be a network call you didn't ask for. Instead, click Check for updates in the footer whenever you like. It fetches the latest release number from GitHub (anonymously — see the FAQ), compares it with the version you're running, and links you to the download page if there's something newer. Nothing is downloaded or installed automatically.
Supported formats
Inputs (formats LocalPix can read)
JPEG · PNG · WebP · AVIF · GIF · HEIF/HEIC · TIFF · BMP · SVG · PSD · PDF · JPEG 2000 · OpenEXR
PDF input renders one page per conversion (pick the page with the PDF page
to convert field that appears when a PDF is in the list). Pages are
rasterised at 192 dpi via MuPDF, fully offline.
Outputs (formats LocalPix can save as)
JPEG · PNG · WebP · AVIF · JPEG XL · JPEG 2000 · OpenEXR · GIF · TIFF · BMP · ICO
Privacy controls
By default, LocalPix strips EXIF, GPS coordinates, and other metadata from converted images. This is the safe choice if you're sharing photos publicly — your camera model, location, software, and timestamps stay private.
- Turn Strip metadata off if you want to keep all original metadata (e.g. preserving camera info for personal archives).
- Turn Preserve color profile on (with Strip on) if you want personal data scrubbed but need colors to render correctly in colour-managed apps (this keeps the ICC profile).
FAQ
Where do my converted files go?
By default, ~/Documents/LocalPix/ (macOS) or Documents\LocalPix\ (Windows). Change this in the app via the Change… button or the Output → Change Output Folder… menu (⌘⇧O / Ctrl+Shift+O).
Why can't I save as HEIC?
HEIC uses the HEVC codec, which has patent licensing complications that make it difficult to include in free, open-source software. LocalPix reads HEIC files (your iPhone photos) without issue, but doesn't write them. AVIF is the modern alternative — same container family, comparable compression, but royalty-free.
Why can't I save as SVG or PSD?
SVG is a vector format; converting a photo to SVG is a fundamentally different task ("tracing") that doesn't make sense for arbitrary images. PSD is a layered Photoshop format; LocalPix can read the flattened image but writing a useful .psd requires the source app's layer structure.
Does LocalPix send my images anywhere?
No. Everything happens on your computer. There's no analytics, no telemetry, no "phone home." You can verify by disconnecting from the internet or watching your firewall — LocalPix will keep working.
The one deliberate exception: clicking Check for updates in the footer makes a single anonymous request to
https://api.github.com/repos/zingiber96/LocalPix/releases/latest to compare version numbers. It carries no identifiers and no data about you or your images, it never runs in the background or on launch, and nothing is downloaded — if a newer version exists you get a link to the release page, and that's it. Don't click the button and LocalPix never touches the network.
Does it work offline?
Yes — once installed, you can be completely offline and LocalPix still works.
How does it compare to online converters?
Online converters upload your image to their server, process it, and let you download the result. That means:
- Slower (upload + download time)
- Privacy-sensitive (their server has your image, possibly logs it)
- Limited (max file size, max batch size, ads)
- Dependent on their service being up
LocalPix avoids all of that.
Can I resize, rotate, or crop images while converting?
Yes — open the Transforms section in the app (collapsed by default; click the chevron). You can resize (max dimension, percentage, or exact dimensions), rotate in 90° increments, flip horizontally or vertically, crop to a fixed aspect ratio (1:1, 4:3, 3:2, 16:9, or custom), and choose a resampling kernel. Transforms apply in a fixed order — crop → orient → resize — so the result is predictable. Global transforms apply to every file; the pencil button on a file row opens per-file settings (format, options, and transforms) that override the globals for just that file.
Can I crop to an exact region instead of an aspect ratio?
Yes — open a file's per-file settings (pencil button) and click Crop… in the Transforms section. Drag to select the region (corner/edge handles, optional aspect lock, live pixel readout); the selection is stored in source pixels and applied before any rotation or resize. Manual crop needs a format the browser can preview (not PSD/HEIF/TIFF/BMP/PDF).
Can I control how output files are named?
Yes — the Filename field next to the output folder takes a template with tokens: {name} (original name), {format}, {width}, {height}, {date}, and {n} (auto-incrementing counter). For example {name}-{width}x{height} produces photo-1920x1080.webp. Leave it empty to keep the original filename.
Will it support [RAW camera files / other format]?
PDF input landed in v1.4 (rendered by MuPDF, one page per conversion). RAW input (DNG, CR2, NEF, ARW, etc.) was investigated for v1.2 — magick-wasm accepts the files but only extracts the small embedded preview thumbnail, not the full demosaiced sensor data, so it's deferred until a real RAW decoder (libraw-wasm or similar) lands in a future version. See CHANGELOG.md and Issues for current status.
What's new in this version?
See CHANGELOG.md.
Issues, ideas, contributions
For developers
LocalPix is an Electron app wrapping a Node.js HTTP server. The renderer is a single hand-written HTML file (no build step). The conversion engine is a hybrid of two image libraries:
- sharp — native libvips bindings, used for the hot path (JPEG, PNG, WebP, AVIF, GIF, TIFF). Fast and battle-tested.
- @imagemagick/magick-wasm — ImageMagick compiled to WebAssembly, used for everything else (HEIC, PSD, BMP, JPEG XL, and future formats). Slower than sharp on common formats but supports ~270 formats out of the box.
Adding a new format is one dispatch table entry per side (server + frontend config). No new dependencies needed.
Project layout
LocalPix/
├── server.js # Express server + ENCODERS dispatch table
├── lib/magick.js # Lazy-init wrapper around magick-wasm
├── electron/
│ ├── main.js # Electron main: window, menus, folder picker, dock-icon swap
│ └── preload.js # contextBridge → window.localpix IPC API
├── public/
│ └── index.html # Single-file frontend (vanilla JS, no build)
├── assets/ # Runtime icon variants (light/dark)
├── build/ # Build-time icon source files
├── CHANGELOG.md
└── package.json # electron-builder config in the "build" key
Requirements
Run from source
git clone https://github.com/zingiber96/WEBPConvert.git localpix
cd localpix
npm install
npm start # plain HTTP server at localhost:3000
npm run app # Electron desktop window (the full LocalPix experience)
Build distributables locally
npm run dist:mac # macOS .dmg (Apple Silicon)
npm run dist:win # Windows installer .exe (x64)
npm run dist:win-all # Windows x64 AND ARM64
npm run dist:all # macOS + Windows x64 in one shot
Output lands in release/. macOS builds require macOS. Windows builds cross-compile cleanly from macOS — electron-builder auto-downloads Wine + NSIS on first run (~25 MB, cached afterward), and the dist:win / dist:win-all / dist:all scripts auto-fetch the Windows-platform sharp native binaries via _prep:win-x64 / _prep:win-arm64 hooks.
Cut a release (recommended path)
Local builds are for development. Actual releases are built by GitHub Actions so they're reproducible and platform-correct — see .github/workflows/release.yml.
# 1. Bump version in package.json + add a `## [x.y.z]` section to CHANGELOG.md
# 2. Commit + push to main
# 3. Tag and push the tag
git tag vx.y.z
git push origin main --tags
A few minutes later, a draft release appears in the Releases page with the DMG + EXE attached and release notes auto-extracted from CHANGELOG.md. Review the draft, then click Publish.
For testing the build pipeline without creating a release, use the workflow_dispatch trigger from the Actions tab — artifacts will be uploaded to the workflow run only.
Run as a headless server (Docker)
For a server-only deployment without a desktop window:
docker compose up --build
# or
docker build -t localpix .
docker run -p 3000:3000 -v "$(pwd)/output:/app/output" localpix
Open http://localhost:3000. Output files persist to the host's ./output via bind mount.
Adding a new output format
- Add an entry to
ENCODERS in server.js (existing entries are good templates — sharp-native ones return pipeline.format().toBuffer(), magick-routed ones go through lib/magick.js).
- Add an entry to
FORMAT_OPTIONS in public/index.html for the UI options panel.
- Add a
<button> to the segmented selector and an <option> to the hidden <select> (kept in sync alphabetically).
That's it — the endpoint logic, dispatch, and per-file UI all flow from these three additions.
Dependencies
| Package | Purpose |
|---|
express | HTTP server |
multer | Multipart upload handling |
sharp | Native image processing for the hot path |
@imagemagick/magick-wasm | WASM ImageMagick for the long-tail formats |
Contributing
Pull requests welcome. For substantive changes (new features, architectural shifts), open an issue first to discuss the approach.
The codebase aims to be readable without a deep dive — single-file frontend, single-file server, no transpilation step on the renderer side. If something feels mysterious, that's a documentation bug; let me know.
