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

#	App	Pricing	Open source	Platforms	Verified facts	Score
1	Caesium Image Compressor	Open source	Yes	Windows, macOS, Web	5 of 5	62.6
2	Clop	Free plan + paid	No	macOS	7 of 7	40.0

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)
2. Clop
Best for: Mac users who share many screenshots and screen recordings and want them smaller automatically
Free plan + paidmacOS
40.0
score / 100
Why switch from ImageOptim
Optimises automatically on copy and in watched folders, and also handles video, PDFs and audio.
Pros
Optimises clipboard images automatically before you paste
Handles images, video, PDFs and audio in one app
All processing on-device, with no cloud upload
One-time Pro licence rather than a subscription
Cons
Mac only, and requires macOS 14 Sonoma or later
Free version caps folder and drop-zone optimisation at 5 files per session
Closed source, unlike ImageOptim or Caesium
Visit Clop Details and reviews
How this score is calculated
Editorial fit ×0.312
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 Clop a good ImageOptim alternative?
Verified facts
7 of 7 verified
Pro licence
€15 lifetime
Checked Oct 30, 2026lowtechguys.com(opens source in a new tab)
Free trial
14 days of Pro features
Checked Oct 30, 2026lowtechguys.com(opens source in a new tab)
Requirements
macOS 14 Sonoma or later
Checked Oct 30, 2026lowtechguys.com(opens source in a new tab)
On-device processing
Yes, no cloud services
Checked Oct 30, 2026lowtechguys.com(opens source in a new tab)
Free version limit
Up to 5 files per drop
Checked Oct 30, 2026lowtechguys.com(opens source in a new tab)
Lifetime price
€15 (Clop Pro lifetime licence)
Checked Nov 1, 2026lowtechguys.com(opens source in a new tab)
Free plan
Yes, up to 5 dropped files at a time
Checked Nov 1, 2026lowtechguys.com(opens source in a new tab)