Measurement · 3 min read
Is a Mac screenshot smaller as a JPG than as a PNG?
Only when it contains a photo: a screenshot containing a photo got 89.5% smaller at the median as a JPG, while a screenshot of text got 7.3% larger at the median. That is the result of measuring 20 screenshots on a MacBook Pro on October 19, 2026, where HEIC produced a smaller file than PNG and JPG every time, 70.4% smaller than PNG at the median.
How does JPG do with text, interface and photo?
The more of the image is photo, the more JPG saves: nothing for text at the median, 9.9% for interfaces, 89.5% for photos. Of the 7 text screenshots taken on the MacBook Pro on October 19, 2026, 4 were larger as a JPG than as a PNG, one by 28.4%.
HEIC is clearly smaller than both PNG and JPG in all three groups.
| Content | PNG | JPG | HEIC |
|---|---|---|---|
| Text | 704 KB | 701 KB (+7.3%) | 276 KB (−60.9%) |
| Interface | 640 KB | 573 KB (−9.9%) | 204 KB (−72.9%) |
| Photo | 10.29 MB | 995 KB (−89.5%) | 519 KB (−94.6%) |
The sizes are medians of the 7, 7 and 6 captures in each group. In parentheses is the median of the per-capture differences against the PNG, where plus means larger, so it differs slightly from the ratio of the two medians.
How do you save a Mac screenshot as JPG or HEIC?
In Terminal, with the screencapture command and the option -t jpg or -t heic. On the MacBook Pro on October 19, 2026, screencapture -t heic wrote a smaller file than -t jpg and -t png for every one of the 20 captures.
Without that option, macOS saves screenshots as PNG files (Mac User Guide, checked October 19, 2026); according to the command’s manual page, -t picks a different image format (man screencapture on macOS 27.0.1, checked October 19, 2026). The Preview app converts an existing screenshot to HEIC or JPEG with File > Export (Preview User Guide, checked October 19, 2026).
How much a PNG screenshot saves at half size and with new compression is covered in How much smaller does a Mac screenshot get?.
How was this measured?
The measurement covers 20 screenshots taken on October 19, 2026 on the built-in Liquid Retina XDR display of a MacBook Pro with M5 Pro running macOS 27.0.1.
- Capture: for each content type, the same Chrome window of 2056 × 1290 points, captured one after the other with
screencapture -x -o -l <window>and-t png,-t jpgand-t heic, so without the window shadow. Each capture is 4112 × 2580 pixels at 144 dpi. - Content: 7 captures of text (license and legal pages), 7 of interface (Chrome settings pages, web pages with controls), 6 of photos (macOS desktop pictures, full and cropped).
- Analysis: file size in bytes, median per group; 1 KB is 1,000 bytes, 1 MB is 1,000,000 bytes.
Not measured: full-screen captures instead of a single window, other devices and image quality. The captures themselves are not published.