Lossless vs Lossy Compression — When to Use Each
One preserves every pixel exactly. The other trades a little data for a lot of savings. Here's how to choose correctly, every time.
Lossless vs lossy at a glance
| Attribute | Lossless | Lossy |
|---|---|---|
| Pixel accuracy | 100% — exact reconstruction | Approximate — some data discarded |
| Typical file size | Larger | Smaller, often 60-80% less |
| Best for | Logos, icons, source files, text screenshots | Photos, web delivery, app assets |
| Re-editable safely | ✅ Yes, indefinitely | ⚠️ Degrades with repeated re-saves |
| Formats using it | PNG, WebP (lossless), AVIF (lossless) | JPEG, WebP (lossy), AVIF (lossy) |
How to choose the right mode in TinyPixels
Download and open TinyPixels
Free to install on Mac or Windows — no account needed to start.
Identify your image type
Photo or gradient? Use lossy. Logo, icon, or text screenshot? Use lossless.
Set the mode and quality
For lossy, 75-85% quality is the sweet spot for most photos.
Compress and compare
Check the History tab to confirm the size savings match your expectations.
Why the choice matters
The wrong choice in either direction has a real cost. Using lossless PNG for a photograph wastes bandwidth and storage with no visual benefit. Using lossy JPEG for a logo or screenshot with text introduces visible artifacts exactly where they're most noticeable — sharp edges and small text.
A simple rule of thumb
If the image has continuous tones and gradients — a photograph, a rendered scene — lossy compression at a good quality setting will look identical while being dramatically smaller. If the image has sharp edges, flat colors, or text — a logo, icon, or UI screenshot — lossless compression avoids artifacts that would otherwise be very noticeable.
Never re-compress a lossy file repeatedly
Each time a lossy file like JPEG is opened, edited, and re-saved as JPEG, another round of compression artifacts stacks on top of the previous ones. Keep your working files in a lossless format, and only export to a lossy delivery format as the final step.
Lossless for masters
Keep source and editable files lossless — never lose data prematurely.
Lossy for delivery
Export the final delivery format as lossy at a well-chosen quality setting.
Text and logos stay lossless
Sharp edges and flat colors show lossy artifacts most visibly.
Photos go lossy
Continuous tones compress well with no perceptible difference.
Lossless or lossy, at a glance
A visual version of the decision guide below
A quick decision guide by content type
| Content type | Recommended approach | Why |
|---|---|---|
| Photographs | Lossy | Continuous tones have redundancy lossy compression exploits well, with no visible cost at a good quality setting |
| Logos and brand marks | Lossless | Flat colors and sharp edges show lossy artifacts most visibly, and these assets are reused everywhere |
| Screenshots with text | Lossless | Text edges are exactly where lossy compression artifacts (blockiness, ringing) become distracting |
| UI mockups and app icons | Lossless (or lossy if size matters more) | Similar to logos — flat color areas benefit most from lossless, though some teams accept mild lossy for size |
| Source/master files | Always lossless | Any file you'll edit again should never carry pre-existing lossy artifacts into the next edit |
| Final web/app delivery | Lossy (usually) | The end-user-facing copy rarely needs pixel-perfect accuracy, and file size directly affects load time |
Common mistakes with the lossless/lossy choice
Applying lossy compression to a working/source file
Once lossy artifacts enter a file you'll re-edit, every subsequent save compounds them — keep an untouched lossless master, always.
Defaulting to PNG for everything "to be safe"
Lossless is not automatically "safer" for photographic content — it just means larger files for no visual benefit, since there's no meaningful redundancy in a photo for it to remove.
Not testing a lossy quality setting before a full batch
Quality settings that look fine on one image type can show artifacts on another — spot-check a representative sample per content type before applying broadly.
Assuming "lossy" and "low quality" are synonyms
A well-tuned lossy JPEG at quality 85 can be visually identical to the source — the word "lossy" describes the mechanism, not an inherent quality ceiling.
Frequently asked questions
What is the difference between lossless and lossy compression?
Lossless compression reduces file size without discarding any image data — the original can be reconstructed exactly. Lossy compression discards data the eye is least likely to notice, achieving much smaller files at the cost of some information loss.
When should I use lossless compression?
Use lossless for source files you plan to edit further, logos, icons, screenshots with text, and anything where pixel-perfect accuracy matters more than file size.
When should I use lossy compression?
Use lossy for photographs and delivery-format images where a well-chosen quality setting (typically 75-85%) produces visually identical results at a fraction of the file size — the vast majority of web and app images.
Can a lossy file be converted back to lossless?
No. Once lossy compression discards data, it cannot be recovered. Converting a lossy JPEG to a lossless PNG only stops further loss — it does not restore what was already discarded. Always keep a lossless master if you might need to re-edit later.
Is lossless WebP or AVIF always better than PNG?
Lossless WebP and AVIF generally compress better than PNG for the same pixel-perfect result, thanks to more modern compression algorithms. PNG remains relevant mainly for universal compatibility — every tool and system supports it without question, which newer lossless formats can't yet claim.
Does lossy compression always mean visible quality loss?
Not at well-chosen settings. "Lossy" describes the technical mechanism (some data is discarded), not the perceptual outcome. At quality 75-85 for JPEG or WebP, the discarded data is specifically chosen to be imperceptible to the human eye at normal viewing distances — the tradeoff only becomes visible at more aggressive settings.
Can I mix lossless and lossy within one project?
Yes, and this is standard practice — logos and icons stay lossless while photographic content in the same project goes lossy. There's no requirement to apply one compression philosophy uniformly across every asset type in a single site or app.
Choose the right mode for every image
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