⚡ Thumbp: A Lightweight & Fast WebP Thumbnail Image Generator

Thumbp is a highly efficient thumbnail creation library for Elixir, producing WebP output for optimal speed and performance.

No need for ImageMagick, FFmpeg, libvips, or any other external libraries.

Usage

Read an image file and create a thumbnail:

iex> content = File.read!("./test/assets/images/sample.jpg")
iex> Thumbp.create(content, 320, 240)
{:ok, <<82, 73, 70, 70, 195, 152, 14, 0, 0, 87, 69, ...>>}

The width and height parameters specify maximum bounds rather than exact dimensions; the aspect ratio is preserved.

Adjust the quality with an optional parameter ranging from 0 to 100 (default is 60):

iex> Thumbp.create(content, 160, 120, quality: 50)

You can also specify a target size, though this may increase processing time by approximately 20-80%.

iex> Thumbp.create(content, 160, 120, target_size: 4_096)    # set to 4KB

Tip

The quality and target_size options are mutually exclusive.

Adjust the encoding effort from 0 (fastest) to 6 (smallest file size). The default is 3.

iex> Thumbp.create(content, 160, 120, effort: 5)

Installation

The package can be installed by adding thumbp to your list of dependencies in mix.exs:

def deps do
  [
    {:thumbp, "~> 0.2.0"}
  ]
end

Then, run mix deps.get.

Benchmark

• Input: 1280x960 JPEG (85% quality), 171.5KB
• Output: 320x240 WebP (60% quality), ~2.4KB

mix run benchmark/benchmark.exs

Name                      ips        average  deviation         median         99th %
thumbp                 174.05        5.75 ms     ±3.17%        5.73 ms        6.23 ms
image (libvips)        130.71        7.65 ms     ±3.13%        7.62 ms        8.43 ms

Comparison:
thumbp                 174.05
image (libvips)        130.71 - 1.33x slower +1.91 ms

Measured on macOS Sequoia 15.7.3 arm64, Apple M4 (10) @ 4.46 GHz.

Development

Prerequisites

Note

This library requires the Rust toolchain for compilation.

Follow the instructions at www.rust-lang.org/tools/install to install Rust.

Verify the installation by checking the cargo command version:

cargo --version
# Should output something like: cargo 1.92.0 (344c4567c 2025-10-21)

Then, set the RUSTLER_PRECOMPILATION_EXAMPLE_BUILD environment variable to ensure that local sources are compiled instead of downloading a precompiled library file.

RUSTLER_PRECOMPILATION_EXAMPLE_BUILD=1 mix compile

License

The MIT License