What is a good ImageOptim alternative for Mac?
Levati is an alternative if photos should keep their metadata and screenshots should get much smaller: iPhone photos got 17.8% smaller at the median and kept gain map, Display P3 and EXIF without location, screenshots 84.8%. ImageOptim saved 14.2% and 28.9%, losslessly and without metadata.
This article comes from the maker of Levati; the measurement behind it is described in the method section.
How does an alternative differ from ImageOptim?
In two ways: Levati re-encodes once instead of repacking losslessly, and it keeps the metadata except the location. After Levati, every iPhone photo with a gain map still had it, along with Display P3 and EXIF; after ImageOptim, none had a gain map, a color profile or EXIF data.
By default, ImageOptim removes EXIF metadata such as the GPS position and exactly preserves image quality; it only works lossily once you turn that on in its preferences (ImageOptim, checked October 30, 2026).
How much smaller do photos and screenshots get?
With Levati, iPhone photos got 17.8% smaller at the median, from 5.58 MB to 4.42 MB, with ImageOptim 14.2%, to 4.84 MB. For screenshots the gap was wider: Levati saved 84.8% at half size and 63.5% at full size, ImageOptim 28.9%.
Part of ImageOptim’s saving on photos is the removed metadata, gain map included; Levati writes them back and still comes out smaller because it re-encodes with jpegli.
Where is ImageOptim better?
In fidelity, price and open source: ImageOptim works losslessly by default, every screenshot kept every pixel, and the SSIMULACRA 2 score was 100. For the photos it was 88.7 at the median, above Levati’s 85.6.
ImageOptim is free, open-source software under the GPL, version 2 or later (ImageOptim, checked October 30, 2026). The photos score below 100 despite lossless processing because the color profile is removed: without Display P3, the same color values are read as sRGB. If you want images with no change to the pixels and don’t need the metadata, ImageOptim serves you well.
All values compared
Levati is smaller and keeps everything but the location for photos; ImageOptim keeps every pixel and costs nothing.
| Method | Median saving | SSIMULACRA 2 median (lowest) | Gain map, Display P3, EXIF | Location | Price |
|---|---|---|---|---|---|
| iPhone photos, Levati | 17.8% | 85.6 (83.1) | kept | removed | free for 30 days, Pro $19 once |
| iPhone photos, ImageOptim | 14.2% | 88.7 (83.8) | removed | removed | free |
| Screenshots, Levati, half size | 84.8% | 89.7 (80.9) | – | – | free for 30 days, Pro $19 once |
| Screenshots, Levati, full size | 63.5% | 88.4 (79.7) | – | – | free for 30 days, Pro $19 once |
| Screenshots, ImageOptim | 28.9% | 100 (100) | – | – | free |
SSIMULACRA 2 compares an image with its original and returns a score up to 100; 100 means identical pixels, 90 visually lossless, 85 excellent, 80 very high quality (SSIMULACRA 2 on GitHub, checked October 28, 2026).
How does Levati work day to day?
Levati sits in the menu bar and shrinks what you drop on it; with Automatic on, it takes over new screenshots on the desktop by itself. The original goes to the Trash, and Undo brings it back. After the 30 days, 30 images a month by hand stay free.
The details of the measurement with all metadata are in What’s left of an iPhone photo after Levati and ImageOptim?; why Levati uses jpegli is in jpegli, MozJPEG or jpegoptim: what does each do for phone photos?. More apps, Preview and Caesium among them, are compared in Which app compresses images most on a Mac, and when is a free one enough?.
How was this measured?
The values come from the measurement of October 29, 2026, described in What’s left of an iPhone photo after Levati and ImageOptim?; nothing was measured again for this article.
- Material: 31 JPG photos from iPhone 11 Pro, iPhone 13, iPhone 15 and iPhone 17, and 10 screenshots of public web pages captured headless with Chromium via Playwright 1.64.1 at Retina resolution, 2880 × 1800 pixels; each tool on its own copies, on a MacBook Pro with M5 Pro running macOS 27.2.
- Levati 1.0.2 through the function behind its command-line tool with the app’s default settings; screenshots once at half size and once without.
- ImageOptim 1.9.3 from Homebrew with its default settings, run through the program inside the app bundle.
- Quality: SSIMULACRA 2 from jpeg-xl 0.12.0 against the original at the same resolution; metadata with ExifTool 13.55.
- Analysis: file size in bytes, median; 1 MB is 1,000,000 bytes. Raw data:
docs/messung/rohdaten-vergleich.csvin the website’s repository.
Not measured: ImageOptim’s lossy setting, HEIC and photos from other makers. The photos themselves are not published.