vips-gui

A small Windows desktop app for batch-converting images to JPEG, PNG, WebP or AVIF, using libvips as the engine.

Drag images or folders in, choose a format and its encoder settings, and convert. A preview panel shows the selected image before and after, together with the exact size the output file will be.

Requirements

libvips must be installed separately. It is not bundled.

The app ships as a single .exe with no DLLs of its own, and drives the vips command-line tool as a subprocess. That keeps this program small and avoids shipping a copy of libvips that would go stale.

Installing libvips on Windows

1. Download vips-dev-w64-web-<version>.zip from the libvips releases page.
2. Unzip it somewhere permanent, for example C:\Program Files.
3. Add the vips-<version>\bin folder to your PATH.

libvips 8.13 or newer is required.

If you would rather not touch PATH, either:

• use the Locate vips.exe button the app offers when it cannot find it, or
• set the VIPS_GUI_VIPS_EXE environment variable to the full path of vips.exe.

The app also looks in a few common install locations (C:\Program Files, %LOCALAPPDATA%\Programs, scoop and chocolatey shim directories, and the roots of C: and D:), so an unzipped copy is often found without any setup.

Checking the installation

vips-gui --check

reports which libvips was found, its version, and which output formats it supports, then exits. Useful when the app says libvips is missing and you are sure it is not.

Features

• Batch conversion. Drop in files or whole folder trees; non-images are filtered out automatically.
• Full encoder control. Every relevant libvips save option is exposed, and each control names the option it drives so it can be looked up in the libvips reference.
  • JPEG: quality, progressive, optimised Huffman tables, optimised scans, trellis quantisation, overshoot deringing, quantisation table, chroma subsampling.
  • PNG: compression level, interlacing, palette quantisation (quality, dither, effort), bit depth.
  • WebP: quality, lossless, near-lossless, effort, alpha quality, smart subsampling, minimum-size search, presets.
  • AVIF: quality, lossless, effort, bit depth, chroma subsampling.
• Resizing. Fit inside a bounding box, with an option never to enlarge. Uses libvips thumbnail, which shrinks on load so large sources stay cheap.
• Accurate size prediction. The preview encodes the image at full resolution with your actual settings, so the predicted file size is the size you will get, not an estimate.
• Parallel conversion with a progress bar and a cancel that stops promptly and cleans up partial files.
• Safe by default. Output goes next to each original, and a name collision produces name (1).ext rather than overwriting anything. A JPEG-to-JPEG conversion in place cannot destroy its own input.
• Format gating. A libvips built without libheif has AVIF disabled with an explanation, rather than failing when you press Convert.

Building

Requires a Rust toolchain (1.95 or newer) and, on Windows, the Windows SDK for the resource compiler.

cargo build --release

The result is target/release/vips-gui.exe: one self-contained executable. The Microsoft C runtime is linked statically (see .cargo/config.toml), so it runs without the Visual C++ Redistributable installed.

To regenerate the application icon:

pwsh -File assets/make-icon.ps1

Testing

cargo test

Unit tests run anywhere. The integration tests drive a real vips binary; on a machine without libvips they print why they are skipping and pass, so the suite stays green on a bare checkout.

Some tests deliberately exercise slow AVIF settings and real subprocess cancellation, so the full suite takes around a minute.

Licence

MIT. libvips itself is LGPL-2.1+ and is neither bundled nor linked here; this app only runs it as a separate program.