We compressed 28 photos at 15 settings: here's where quality stops paying off

BananaFast — Sat, 31 Oct 2026 22:32:22 +0000

Most advice on image quality comes down to "use 80 or so." We wanted numbers, so we ran 28 photos through 15 JPEG and WebP settings and recorded the file size and an SSIM score for each one.

The short version: going from JPEG quality 95 to 82 cut the typical photo by about half, and the SSIM score only moved from 0.998 to 0.978. Below that, each step saved less.

Disclosure: we make BananaFast, a free set of in-browser photo tools, and this test uses the same encoder libraries as those tools. The data is free to reuse either way.

The results

Each row is the median across all 28 photos, which were 10.8 megapixels at the median. "Saved" compares each photo with its own JPEG at quality 95. SSIM runs from 0 to 1, where 1 means identical to the source.

Format	Quality	Typical size (KB)	Saved	SSIM
JPEG	95	2,608	0%	0.998
JPEG	92	2,076	15%	0.996
JPEG	90	1,932	20%	0.997
JPEG	85	1,446	41%	0.986
JPEG	82	1,172	51%	0.978
JPEG	80	1,071	54%	0.974
JPEG	75	832	65%	0.967
JPEG	70	720	69%	0.961
JPEG	65	628	73%	0.954
JPEG	60	570	76%	0.944
JPEG	50	463	80%	0.934
WebP	90	1,511	38%	0.985
WebP	80	840	65%	0.969
WebP	70	568	76%	0.957
WebP	60	487	78%	0.949

What stood out

The first cuts are the cheapest. Quality 95 to 82 saved about 51% for 0.020 of SSIM. Quality 60 to 50 saved only about 4 more percentage points for another 0.010.

WebP helps, but compare results rather than setting numbers. WebP at quality 80 was about 26% smaller than JPEG at quality 82, with an SSIM about 0.009 lower. The two quality scales aren't the same.

The same setting gives very different sizes. At JPEG quality 82, plant photos ran about 178 KB per megapixel and food photos about 85 KB. Those groups are small (4 and 2 photos), but detailed scenes do cost more.

Quality alone rarely hits a small file limit. Upload forms and web guides often ask for under 500 KB or 1 MB. Here's how many photos got there at their full pixel size:

JPEG quality	Under 500 KB	1 MB or less
82	1 of 28	7 of 28
75	4 of 28	17 of 28
60	10 of 28	25 of 28
50	17 of 28	26 of 28

Even at quality 50, 11 of the 28 were still over 500 KB. If you have a small limit, you'll usually need to reduce the pixel dimensions too. This test didn't measure resizing, only how far quality alone gets you.

How we tested

Photos: 28 photographs from Wikimedia Commons, all marked CC0: people, landscapes, cities, night scenes, plants, food and indoor scenes.
Encoders: MozJPEG and libwebp through the jSquash libraries, run on a Mac on October 30, 2026.
Similarity: SSIM on brightness only, with an 11-pixel window.

The limits

It's a small sample. 28 photos can't represent every kind of picture, so treat this as a guide.
The sources were already compressed. These are JPEG files as published, not camera originals, and that can flatter the scores at high settings.
SSIM isn't your eyes. It's a math score, and we didn't run a test with human viewers, so we don't claim which setting "looks the same." Brightness-only SSIM also ignores color.
Medians don't always move smoothly. JPEG 92 scored slightly below 90 in the table above (0.996 and 0.997). We haven't looked into why, so the per-photo data may be more useful than that one row.

What we'd do with this

These are starting points from this test, not rules:

For general web photos, try JPEG around quality 82, or WebP around 80 if your platform takes it.
For photos you plan to print or edit again, stay at 90 or higher.
For a hard file size limit, resize first and then compress.
Check low settings with your own eyes on your own images.

Get the data

The full results are a free CSV: every photo at every setting, with a link to each source image. The original write-up is here. Please link to it if you cite the numbers.

If you run this on your own images and get something different, we'd like to hear about it in the comments, especially from anyone testing with camera originals or a color-aware metric.

Image size cheat sheet for 2026 (social, shops, email, visa photos)

BananaFast — Thu, 22 Oct 2026 19:35:41 +0000

If you build sites or apps, you keep looking up the same numbers: how wide an Instagram post is, what X does to a header, how small a visa photo has to be. Here they are on one page. Every number comes from the platform's own help pages.

Social media

Image	Size (px)
Instagram feed post	1080 wide, 1080 × 1080 to 1080 × 1440
Instagram / Facebook story	1080 × 1920
Facebook Page profile	320 × 320 (shown as a circle)
Facebook Page cover	851 × 315
X profile photo	400 × 400
X header	1500 × 500 (up to 60 px cropped top and bottom)
LinkedIn profile background	1584 × 396
LinkedIn Company Page cover	1512 × 256
YouTube thumbnail	3840 × 2160 (min 640 wide)
Pinterest pin	1000 × 1500

Online shops

Marketplace	Size
Etsy	2000 px or more on each side
eBay	at least 500 × 500, about 1600 × 1600 recommended
Shopify	2048 × 2048 for square images

Attachments

Service	Limit
Gmail	25 MB per email
Outlook.com	25 MB per email
Discord (free)	20 MB per file

Email encoding adds about a third, so aim for roughly 18 MB of photos in Gmail and 14 MB in the Outlook desktop app.

US visa photo files

Photo	Size	File
Visa (DS-160 / DS-260)	square, 600 to 1200 px	JPEG, 240 KB or less
DV lottery	exactly 600 × 600	JPEG, 240 KB or less

The full sheet, with a source link on every row, profile-photo notes and FAQs, is here: Photo size cheat sheet for 2026. I update the date at the top whenever a platform changes its numbers.

If you need to hit one of these sizes, BananaFast's resize tool does it in the browser, so nothing is uploaded.

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