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ImageOptim alternatives: 2 apps ranked by verified data

Facts checked Nov 1, 2026AppBreakup editorialHow we rank

Common reasons people leave ImageOptim: mac only, and can be slow on large PNGs with Zopfli and PNGOUT enabled. We ranked 2 alternatives by how directly each one replaces ImageOptim, then by reviews, real visits and how recently each app's facts were checked against its own website. Caesium Image Compressor currently ranks first.

Quick comparison

#AppPricingOpen sourcePlatformsVerified factsScore
1Caesium Image Compressor logoCaesium Image CompressorOpen sourceYesWindows, macOS, Web5 of 562.6
  1. Caesium Image Compressor logo

    1. Caesium Image CompressorTop pick

    Best for: People who need to batch-compress folders of photos for free on Windows or Mac

    Open sourceWindows, macOS, Web

    62.6

    score / 100

    Why switch from ImageOptim

    Free, open-source batch compressor for Windows and Mac with a real-time preview and folder support.

    Pros

    • Free and open source with no file limits
    • Batch processing of whole folders with structure preserved
    • Real-time preview before compressing

    Cons

    • No official Linux build on the download page
    • Interface is functional rather than polished
    Visit Caesium Image Compressor Details and reviews
    How this score is calculated
    Editorial fit ×0.387
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.1585
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Caesium Image Compressor a good ImageOptim alternative?

    Verified facts

    5 of 5 verified
    License
    GPL-3.0
    Checked Oct 29, 2026github.com(opens source in a new tab)
    Formats
    JPG, PNG, WebP, TIFF
    Checked Oct 29, 2026github.com(opens source in a new tab)
    Windows
    Windows 10 (1809) or later
    Checked Oct 29, 2026saerasoft.com(opens source in a new tab)
    macOS
    macOS 12 or later
    Checked Oct 29, 2026saerasoft.com(opens source in a new tab)
    Command line
    Yes
    Checked Oct 29, 2026saerasoft.com(opens source in a new tab)

The best ImageOptim alternative for…

The highest-ranked app in this list for each need.

Caesium Image Compressor logo

Best ImageOptim alternative for most people

Caesium Image Compressor

Free, open-source batch compressor for Windows and Mac with a real-time preview and folder support.

Caesium Image Compressor logo

Best ImageOptim alternative for a free option

Caesium Image Compressor

Free, open-source batch compressor for Windows and Mac with a real-time preview and folder support.

Clop logo

Best ImageOptim alternative for a free plan you can upgrade

Clop

Optimises automatically on copy and in watched folders, and also handles video, PDFs and audio.

Caesium Image Compressor logo

Best ImageOptim alternative for open source

Caesium Image Compressor

Free, open-source batch compressor for Windows and Mac with a real-time preview and folder support.

Caesium Image Compressor logo

Best ImageOptim alternative for Mac

Caesium Image Compressor

Free, open-source batch compressor for Windows and Mac with a real-time preview and folder support.

Caesium Image Compressor logo

Best ImageOptim alternative for Windows

Caesium Image Compressor

Free, open-source batch compressor for Windows and Mac with a real-time preview and folder support.

Caesium Image Compressor logo

Best ImageOptim alternative for working in the browser

Caesium Image Compressor

Free, open-source batch compressor for Windows and Mac with a real-time preview and folder support.

ImageOptim alternatives: common questions

What is the best alternative to ImageOptim?

Caesium Image Compressor ranks first right now. Free, open-source batch compressor for Windows and Mac with a real-time preview and folder support.

Is there a free alternative to ImageOptim?

Yes. Caesium Image Compressor (open source) and Clop (free plan + paid) have a free option. Check each app's verified facts for current plan limits.

Is there an open-source alternative to ImageOptim?

Yes: Caesium Image Compressor.

Why do people switch from ImageOptim?

The complaints we hear most: mac only; can be slow on large PNGs with Zopfli and PNGOUT enabled; no WebP or AVIF conversion in the Mac app.

How is this list ranked?

Every app is scored with the same published formula: how directly it replaces ImageOptim, reviews (weighted by verification), visits from AppBreakup, how recently its facts were checked against its own website, and reader votes.