SuperViewer by Bitcoin.com

A fast image viewer for Windows, built in Rust.

Quickstart

1. Run the installer (no admin required)

installer\install.bat

2. Set SuperViewer as the default application for your preferred image formats (eg. png) in the window that opens

3. Open an image by double clicking on it in Windows Explorer

4. To Uninstall, run:

installer\uninstall.bat

Screenshot

Windows Photos vs SuperViewer

Windows Photos	SuperViewer

Features

• Fast startup (~30 ms)
• Smooth 60+ FPS pan & zoom
• Browse images in folder with (← / →)
• Fast loading of upcoming images
• Drag and drop
• Fullscreen mode
• Rotate and flip (GPU-based, zero CPU cost)
• File details in status bar (filename, resolution, zoom)
• Single self-contained executable

Supported Formats

JPEG, PNG, Web, BMP, TIFF, GIF, AVIF

Keyboard Shortcuts

Key	Action
Esc	Quit
F / F11	Toggle fullscreen
0 / Numpad 0	Fit to screen
1 / Numpad 1	Zoom to 100% (1:1 pixels)
R	Rotate 90 clockwise
H	Flip horizontal
V	Flip vertical
Left	Previous image
Right / Space	Next image
Mouse drag	Pan
Scroll wheel	Zoom to cursor

What problem we solve

Most image viewers today feel heavier than they should.

They often:

• take noticeable time to launch

• stutter when moving through large folders

• consume excessive memory

• depend on large frameworks or runtimes

• feel sluggish with high-resolution photos

SuperViewer exists to do one thing well: to open images immediately and let you move through them quickly.

Why it is faster

SuperViewer keeps the stack simple and close to the system:

• Native Windows app: no heavy frameworks or startup cost

• GPU rendering: zoom and transforms handled by your graphics card, not the CPU

• Background decoding: upcoming images load ahead of time while you view the current one

• In-memory cache: previously viewed images reopen instantly

• Single binary: no external dependencies or runtimes to load

Result: less waiting, smoother interactions.

Benchmarks (The nerdy stuff)

Test machine: Windows 11, i7-11600H, RTX 3050 Ti
Disk cache warm, median of 10 runs.

Benchmark scripts and raw data in benchmarks/.

Cold start (process launch → window visible)

Image	SuperViewer	IrfanView	JPEGView	qView
4K JPEG	37 ms	86 ms	134 ms	192 ms
4K PNG	39 ms	97 ms	389 ms	190 ms
1080p JPEG	37 ms	84 ms	86 ms	192 ms
4K WebP	48 ms	84 ms	232 ms	184 ms

Folder navigation (100 sequential images)

Viewer	Median
IrfanView	61 ms
JPEGView	62 ms
qView	62 ms
SuperViewer	63 ms

Binary size

Viewer	Exe	Total Install	Files	DLLs
SuperViewer	10 MB	10 MB	1	0
IrfanView	2.4 MB	8.3 MB	37	12
JPEGView	2.8 MB	10.3 MB	54	11
qView	1.5 MB	96.8 MB	108	71

Memory

SuperViewer uses a cache (max ~512 MB) to enable fast back/forward navigation. The cache is used as images are opened, so usage grows gradually and stays low if you view just a few files. This value is just a limit, not memory reserved when starting the app.

Architecture

crates/
  viewer-core/      Decode, cache, transforms, directory nav, async pipeline
  viewer-render/    wgpu GPU context, texture upload, shader-based renderer, overlay status bar
  viewer-win32/     Raw Win32 window, WndProc, DPI, drag-drop, fullscreen
  viewer-cli/       CLI argument parsing (clap)
  viewer-app/       Composition root: event loop, state machine, keybindings
assets/
  shaders/
    quad.wgsl       Vertex + fragment shader (transform uniforms)
    overlay.wgsl    Status bar overlay shader (rect-positioned textured quad)

Building

Prerequisites

• Rust (stable toolchain)
• MSVC Build Tools
• CMake (for turbojpeg)

Build

# Debug
cargo build

# Release (optimized, ~10 MB)
cargo build --release

The release binary is at target/release/superviewer.exe.

Installing

# Run the installer (no admin required)
installer\install.bat

This copies superviewer.exe to %LOCALAPPDATA%\SuperViewer\, registers file associations for JPEG, PNG, BMP, WebP, TIFF, GIF, and AVIF, then opens Windows Settings where you can set SuperViewer as your default app.

To pass a custom exe path (e.g. during development):

.\installer\install.ps1 -ExePath "target\release\superviewer.exe"

To ininstall

installer\uninstall.bat

Removes all registry entries and the install directory. Use -KeepFiles to only remove associations.

Run

# Open an image
cargo run --release -- photo.jpg

# Or run the binary directly
target/release/superviewer.exe C:\path\to\image.png

Testing

See TESTING.md for a full manual test checklist. Quick start:

# Generate test images (Python 3, no dependencies)
python tests/generate_test_images.py

# Run the viewer against test images
target/release/superviewer.exe tests/images/test_gradient.bmp

Build Dependencies

Crate	Version	Purpose
wgpu	28	GPU rendering (DX12/Vulkan)
windows	0.61	Win32 API
turbojpeg	1.4	Fast JPEG decode
image	0.25	PNG, BMP, TIFF, GIF, AVIF decode
webp	0.3	WebP decode
fast_image_resize	5.1	Display downsampling
rayon	1.10	Thread pool for decode
crossbeam-channel	0.5	Bounded channels for pipeline
clap	4	CLI parsing
bytemuck	1	Safe transmute for GPU uniforms

Made with <3 at Bitcoin.com