explaingit

lymphatus/caesium-image-compressor

★ 5,912C++Audience · generalComplexity · 1/5LicenseSetup · easy

TLDR

A desktop app for batch-compressing JPG, PNG, and WebP images to smaller file sizes while keeping them looking sharp, available on Windows, macOS, and Linux.

Mindmap

mindmap
  root((repo))
    What it does
      Image compression
      Batch processing
      Quality control
    Formats
      JPG
      PNG
      WebP
    Platforms
      Windows
      macOS
      Linux
    Extras
      19 languages
      Web version
      Open source
Click or tap to explore — scroll the page freely

Code map

Detail Auto

An interactive map of this repo's files and how they connect — its source is parsed live in your browser. Click Visualize to build it.

filefunction / class

Things people build with this

USE CASE 1

Compress a batch of product photos before uploading them to a website or e-commerce store

USE CASE 2

Reduce image file sizes for email attachments without visible quality loss

USE CASE 3

Optimize app screenshots or marketing images to improve page load speed

USE CASE 4

Resize and compress high-resolution photos to make them shareable on social media

Tech stack

C++Qtlibcaesium

Getting it running

Difficulty · easy Time to first run · 5min

Download the installer from the releases page, the main branch may contain unstable code.

Open source, use and distribute freely.

In plain English

Caesium is a desktop application for reducing the file size of images. You give it a batch of photos in JPG, PNG, or WebP format, set how much you want to compress them, and it produces smaller versions while keeping the image looking as close to the original as possible. You can also reduce the resolution at the same time if you want. The tool is designed for everyday tasks: making photos small enough to send by email, upload to a website, or store without taking up too much space. It works as a standard desktop application with a graphical interface, so you drag in your files, adjust a quality setting, and click to compress. A web-based version is also available at caesium.app if you want to try it without installing anything. Caesium runs on Windows (10 or later), macOS (12 or later), and Linux. Installers and portable versions for Windows are on the releases page, as is a DMG package for macOS. Linux users can compile from source or use a third-party binary build. The application is available in 19 languages, including English, German, French, Spanish, Russian, Chinese (Simplified and Traditional), Japanese, and several others, with translations contributed by the community. If a translation for your language is missing or incomplete, you can contribute one by editing a provided translation file and submitting a pull request. Version 3.0 is currently in early development. The project is open source and built on top of a companion library called libcaesium, which handles the actual compression work. The main branch may contain unstable code, so downloading from the releases page is recommended for general use.

Copy-paste prompts

Prompt 1
How do I batch compress 500 JPG photos in Caesium while keeping quality above 80 percent?
Prompt 2
Set up Caesium to resize images to a maximum width of 1200 pixels and compress them at the same time
Prompt 3
What quality settings in Caesium give the best file size reduction for PNG screenshots without visible loss?
Prompt 4
How do I build Caesium from source on Linux and run it as a command-line tool for automated image optimization?
Open on GitHub → Explain another repo

← lymphatus on gitmyhub — every repo by this author, as a profile.

Verify against the repo before relying on details.