Measurement · 4 min read
How much smaller does a Mac screenshot get?
A screenshot from the Retina display of a MacBook Pro gets 90.5% smaller at the median when it is reduced to half its width and height and then compressed as a PNG: 1.22 MB becomes 146 KB. That is the result of measuring 24 screenshots on October 19, 2026, where compression alone saved 78.4% at the median and half size alone saved 65.3%.
Why is a Mac screenshot so large?
A screenshot is large because macOS saves it as a PNG and a Retina display draws every point with four pixels. On the built-in display of a MacBook Pro with M5 Pro, each of the 24 captures from October 19, 2026 measured 4112 × 2658 pixels at 144 dpi; the median file was 1.22 MB, and captures with a photo on the display were up to 14.12 MB.
Apple names PNG as the file format for screenshots (Mac User Guide, checked October 19, 2026) and describes four pixels for each point on high-resolution displays, a scale factor of 2 (High Resolution Guidelines for OS X, checked October 19, 2026).
How much does halving the size save on its own?
Halving the width and height on its own makes a screenshot 65.3% smaller at the median, from 1.22 MB to 551 KB. Across the 24 captures from October 19, 2026 on the MacBook Pro, the saving ranged from 45.2% to 75.8%. The 4112 × 2658 pixels become 2056 × 1329, a quarter of the pixels, and as many as the display shows in points.
Text shrinks less than photos: pages of text got 58.6% smaller at the median, photos 70.5%.
How much does PNG compression save on its own?
PNG compression on its own makes a screenshot 78.4% smaller at the median, from 1.22 MB to 275 KB, with the pixel count unchanged. Measured on October 19, 2026 on the same 24 captures from the MacBook Pro, the saving ranged from 66.1% to 84.2%.
The compression used pngquant, which shrinks a PNG with lossy compression based on a newly generated color palette (pngquant.org, checked October 19, 2026), followed by oxipng, a lossless PNG optimizer (oxipng on GitHub, checked October 19, 2026).
How much do both steps save together?
Both steps together make a screenshot 90.5% smaller at the median, from 1.22 MB to 146 KB. Across the 24 captures from October 19, 2026 on the MacBook Pro, the saving ranged from 82.6% to 95.5%, and the resulting files from 46 KB to 1.25 MB.
The combination saved more than either step alone on every one of the 24 captures, about 12 percentage points more than compression alone at the median.
| Method | Median size | Median saving | Saving range |
|---|---|---|---|
| Original | 1.22 MB | 0% | 0% |
| Halved | 551 KB | 65.3% | 45.2% to 75.8% |
| PNG compression | 275 KB | 78.4% | 66.1% to 84.2% |
| Both | 146 KB | 90.5% | 82.6% to 95.5% |
Does the saving depend on what is on the display?
The percentage saved depends little on the content, but the resulting size depends on it a great deal: with both steps, text, interface and photo got 88.9%, 91.6% and 92.2% smaller at the median. Across the 8 captures per group from October 19, 2026 on the MacBook Pro, a photo on the display was still 770 KB afterwards, about seven times the 109 KB of a page of text.
For photos, halving the size saves almost as much as compression; for text and interface, compression saves considerably more.
| Content | Original | Halved | PNG compression | Both |
|---|---|---|---|---|
| Text | 1.01 MB | 419 KB (58.6%) | 211 KB (78.9%) | 109 KB (88.9%) |
| Interface | 1.12 MB | 439 KB (65.3%) | 239 KB (80.2%) | 115 KB (91.6%) |
| Photo | 11.13 MB | 3.02 MB (70.5%) | 2.79 MB (72.0%) | 770 KB (92.2%) |
All values are medians of the 8 captures in each group, with the saving against the original in parentheses.
How was this measured?
The measurement covers 24 screenshots taken on October 19, 2026 with screencapture from the built-in Liquid Retina XDR display of a MacBook Pro with M5 Pro running macOS 27.0.1.
- Display: scaled to 2056 × 1329 points, each capture 4112 × 2658 pixels at 144 dpi as a PNG, the full display including the menu bar and the browser window.
- Content: 8 captures each of text (license and legal pages in the browser), interface (Chrome settings and extensions pages, web pages with controls) and photo (macOS desktop pictures, full and cropped).
- Halving: reduced to half the width and height with Apple’s ImageIO and saved as a PNG at 72 dpi.
- PNG compression: with the Levati command-line tool, which runs pngquant 3.0.3 with
--skip-if-largerfollowed by oxipng 10.2.1. - Both: the halved file, then the same compression.
- Analysis: file size in bytes, median and range from minimum to maximum; 1 KB is 1,000 bytes, 1 MB is 1,000,000 bytes.
Other devices, other scaling settings, HDR screenshots and non-Retina displays were not measured; results there will differ. The captures themselves are not published.