MiniPx vs ImageOptim

ImageOptim is a beloved Mac app for lossless image compression. MiniPx works everywhere — any browser, any device. Here is how they actually stack up.

Quick verdict

If you are on a Mac and only need PNG/JPEG optimization, ImageOptim is excellent — especially for lossless PNG compression via pngquant and zopfli. But if you use Windows, Linux, or mobile, or need format conversion, HEIC support, target-size compression, or PDF tools, MiniPx is the more versatile choice.

Feature comparison

Feature

MiniPx

ImageOptim

Platform

Any browser (Win, Mac, Linux, mobile)

Mac only

Privacy

Client-side (browser)

Local (desktop app)

Install required

Yes (.dmg download)

Formats

JPEG, PNG, WebP, AVIF, HEIC, SVG, PDF

JPEG, PNG, GIF, SVG

HEIC support

Yes — convert & compress

Format conversion

Yes — any format to any format

No — optimize only

Target size

Yes — compress to exact KB

Batch processing

Yes, unlimited

PNG lossless quality

Good (Canvas API)

Excellent (pngquant + zopfli)

Offline capable

Yes (PWA)

Yes (native app)

Price

Free

The platform question

This is the biggest differentiator. ImageOptim is Mac-only — there is no Windows version, no Linux version, no mobile app. If you are on a Mac and that is your only machine, this is not a problem. But the moment you need to compress images on your phone, a Windows PC, or a Chromebook, ImageOptim is simply not an option.

MiniPx runs in any modern browser — Chrome, Safari, Firefox, Edge — on any operating system. Open the URL, drop your images, done. No install, no app store, no compatibility issues.

Privacy — both keep files local

This is one area where both tools are equally strong. ImageOptim processes images on your Mac — nothing gets uploaded. MiniPx processes everything in your browser — nothing gets uploaded either. If privacy is your top concern, both are solid choices. The difference is that MiniPx gives you that same privacy on any device, not just a Mac.

Where ImageOptim wins

ImageOptim's PNG compression is genuinely excellent. It chains multiple tools — pngquant for lossy reduction, zopfli for lossless recompression, and oxipng for further optimization. For PNG-heavy workflows (web design, screenshots, UI assets), ImageOptim often produces smaller PNGs than browser-based tools.

It also integrates beautifully into Mac workflows — drag files from Finder, right-click to optimize, even Automator actions for batch jobs. If you are a Mac-only designer who primarily works with PNG and JPEG, ImageOptim is hard to beat.

Where MiniPx wins

Format support is where MiniPx pulls ahead. HEIC from iPhones, AVIF from modern browsers, WebP, PDF, SVG — MiniPx handles them all. ImageOptim does not convert between formats at all — it only optimizes files in their existing format.

MiniPx also offers target-size compression (shrink to exact KB), which matters a lot for government form uploads, exam applications, and email attachments. ImageOptim gives you a quality slider but no way to hit a specific file size target.

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Try MiniPx Free — Works on Any Device →

No install. No Mac required. 7+ formats.

MiniPx vs ImageOptim — Free, Fast & Private

ImageOptim has been a staple in the Mac design community for years. It does one thing and does it well: strip unnecessary metadata and recompress images without visible quality loss. The app is lightweight, fast, and free.

But the web has evolved. People work across devices — a MacBook at the office, a Windows desktop at home, a phone on the go. Image formats have expanded beyond PNG and JPEG. And workflows increasingly demand more than just "make this file smaller."

MiniPx covers those gaps. Convert HEIC to JPG for a government form, compress a batch of product photos to under 200KB each, turn a PDF into images — all from a browser tab. It is not trying to replace ImageOptim's excellent PNG pipeline. It is solving the broader problem of image processing on any device.

Which should you pick?

If you are a Mac-only designer who primarily optimizes PNGs, ImageOptim remains a great tool. For everyone else — Windows users, mobile users, people who need format conversion or target-size compression — MiniPx is the more complete solution. And since both are free and private, you can use both.

For more comparisons, see our best image compressor 2026 roundup where we test popular tools side by side.

How it works

Open MiniPx in your browser: Go to minipx.com on any device. No download or signup needed.
Drop your images: Drag and drop any images — JPEG, PNG, WebP, HEIC, AVIF, or SVG.
Pick compression settings: Choose Smart for automatic quality, or set a target file size.
Download optimized files: Save your compressed images. They never left your browser.

Frequently asked questions

Is MiniPx better than ImageOptim?

It depends on your needs. MiniPx works on any device and supports more formats including HEIC, AVIF, and format conversion. ImageOptim produces better lossless PNG compression on Mac. Both are free and process files locally.

Does ImageOptim work on Windows?

No. ImageOptim is Mac-only. There is no official Windows version. MiniPx works on Windows, Mac, Linux, and mobile through any modern browser.

Can ImageOptim convert HEIC to JPG?

No. ImageOptim optimizes files in their existing format — it does not convert between formats. MiniPx can convert HEIC, AVIF, WebP, PNG, and more to any supported output format.

Which has better PNG compression?

ImageOptim, by a meaningful margin. It uses pngquant and zopfli, which are specialized PNG optimization tools that typically produce 10-30% smaller PNGs than browser-based Canvas API compression.

Can I use both tools together?

Absolutely. Use MiniPx for format conversion, HEIC handling, target-size compression, and working on non-Mac devices. Use ImageOptim for final-pass PNG optimization on your Mac.