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JPG Quality Settings, Tested: What Each Level Really Costs
The short answer: we generated three test images — a photo, a graphic, and a mix of both — and saved each as a JPEG at six quality levels, measuring every byte. Dropping from quality 95 to 85 cuts a photo's file size roughly in half with no visible difference — and for graphics, JPEG is worse than PNG at every quality level.
How did we test this?
Honest methodology, so you can judge the numbers: we used Python's Pillow (PIL 10.2.0) to generate three 1200×800 test images — a photo-like gradient with grain and soft shapes, a flat-color graphic with text (like a logo or screenshot), and a mixed photo with a text banner. Each was saved as a PNG baseline (optimize=True), then as JPEG at quality 95, 90, 85, 75, 60 and 40 (optimize=True). File sizes were measured in bytes; PSNR was computed against the PNG original as a sanity check. These are synthetic images, so treat the absolute numbers as illustrating the pattern — your own photos will differ, which is exactly why we built a free tool to test yours.
What does each quality level cost on a photo?
Our photo-like test image weighed 2,170.3 KB as a PNG. Here's what each JPEG quality level did to it:
| Quality | File size | % of PNG |
|---|---|---|
| PNG (baseline) | 2,170.3 KB | 100% |
| JPEG 95 | 534.7 KB | 24.6% |
| JPEG 90 | 355.1 KB | 16.4% |
| JPEG 85 | 257.9 KB | 11.9% |
| JPEG 75 | 162.4 KB | 7.5% |
| JPEG 60 | 97.2 KB | 4.5% |
| JPEG 40 | 55.7 KB | 2.6% |
The 95→85 step is the headline: roughly half the bytes (534.7 → 257.9 KB) with PSNR essentially flat (26.2 → 25.2 dB) — visually identical at normal viewing distance. Below 60, compression artifacts start becoming visible on most photos.
Why is JPEG terrible for graphics?
Our flat-color graphic with text weighed just 7.7 KB as a PNG. Every JPEG version was bigger — much bigger:
| Quality | File size | % of PNG |
|---|---|---|
| PNG (baseline) | 7.7 KB | 100% |
| JPEG 95 | 45.5 KB | 594% |
| JPEG 85 | 33.7 KB | 441% |
| JPEG 75 | 28.7 KB | 375% |
| JPEG 60 | 24.9 KB | 325% |
| JPEG 40 | 21.0 KB | 274% |
Flat colors and sharp text are PNG's best case and JPEG's worst: JPEG invents ringing noise around every sharp edge, so it needs more data to describe a "simple" graphic than PNG does. Rule of thumb confirmed by measurement: logos, text, and screenshots stay PNG — converting them to JPEG bloats the file and blurs the edges. (Use our PNG to JPG converter only for photographic PNGs.)
What about a photo with text on it?
The mixed image (photo + text banner) started at 1,663.9 KB as PNG:
| Quality | File size | % of PNG |
|---|---|---|
| PNG (baseline) | 1,663.9 KB | 100% |
| JPEG 95 | 433.5 KB | 26.1% |
| JPEG 90 | 298.5 KB | 17.9% |
| JPEG 85 | 222.4 KB | 13.4% |
| JPEG 75 | 143.8 KB | 8.6% |
| JPEG 60 | 88.7 KB | 5.3% |
| JPEG 40 | 53.3 KB | 3.2% |
The pattern matches the pure photo almost exactly — the photographic background dominates the byte count, and the overlaid text stayed readable down to quality 75 in our test.
Which quality setting should you actually use?
- Photos for the web: 75–85. That's the sweet spot our measurements point to. Use 85 when you want a safety margin, 75 when every kilobyte counts.
- Below 60: visible artifacts on most photos — blockiness in skies and gradients. Only for thumbnails or extreme size limits.
- Graphics, logos, text, screenshots: don't use JPEG at all. Our test says PNG wins by 3–6×.
- The 95→85 step: about 50% smaller with no visible change on photos. If your exporter defaults to 95+, you're leaving half the bytes on the table.
Try it on your own images
Lab numbers on synthetic images only tell you the pattern — your camera, your grain, your subject. The real test takes ten seconds: drop your photo into our free JPG compressor, slide the quality, and watch the live file size. No signup, and your image never leaves your device. For bulk jobs, the image compressor targets an exact file size automatically.
Frequently asked questions
Is JPEG quality 100 worth it?
We tested up to quality 95, and the trend is unambiguous: each step above 90 buys you almost nothing. On our photo, quality 95 already cost more than double the bytes of quality 85 (534.7 vs 257.9 KB) with no visible gain — and 100 would cost substantially more still. For photos, 85 is the sane ceiling.
Will I see the difference between quality 95 and 85?
On our photo test, no — at normal viewing distance the two are visually identical, while 85 uses roughly half the bytes. The measured PSNR barely moved (26.2 vs 25.2 dB). If you pixel-peep a 200% zoom on fine texture you might spot a difference; your visitors won't.
Why did my logo get bigger when I converted it to JPG?
Because JPEG is engineered for photographs, not flat graphics. In our measurement, even the lowest-quality JPEG of a simple graphic (21.0 KB at quality 40) was still 274% of the PNG original (7.7 KB). JPEG adds ringing artifacts around sharp edges, which costs bytes instead of saving them. Keep logos and text as PNG.
What JPEG quality should I use for website images?
75–85 for photographs, based on our measurements — that's where the size/quality curve bends in your favor. Just as important: export at the display size. A 4000px photo shown at 1200px wastes most of its bytes regardless of quality setting; resize first, then pick quality.
Are these results true for my photos?
Directionally, yes — the shape of the curve (steep savings 95→75, artifacts below 60, JPEG-bloat on graphics) holds across images. Absolute numbers shift with your content: grainy or highly detailed photos compress less, clean studio shots compress more. The honest move is to test your own files with our free compressor and compare side by side.