Guides
How to Compress an Image Without Losing Quality
Shrink image files without visible quality loss: resize first, pick the right format, use JPEG quality 75–85 or WebP/AVIF, and strip metadata.
To compress an image without visible quality loss, resize it to the size it will actually be shown at, then save it in the right format at a sensible setting: JPEG at quality 75–85 or WebP/AVIF for photos, PNG or lossless WebP for screenshots and graphics. Strip the metadata while you're at it. Done in that order, a 5 MB phone photo usually ends up at a few hundred kilobytes and looks the same on screen.
Lossless vs lossy: what "without losing quality" really means
There are two kinds of compression:
- Lossless keeps every pixel exactly. PNG is always lossless; WebP and AVIF have lossless modes. Decompress it and you get the original back, bit for bit. Savings are real but limited, especially on photos.
- Lossy throws away detail the eye is unlikely to notice. JPEG is lossy; WebP and AVIF have lossy modes. Savings are large, and at good settings the loss is invisible at normal viewing size.
So "without losing quality" usually means one of two things: truly lossless (smaller, never different) or visually lossless (much smaller, no difference you can see). For photos, visually lossless is almost always what you want.
| Image type | Best format | Mode |
|---|---|---|
| Photo for web or email | JPEG, WebP or AVIF | Lossy, quality 75–85 |
| Photo you'll edit again | Keep the original | None, work from the source |
| Screenshot, text, UI | PNG or lossless WebP | Lossless |
| Logo, icon, flat graphic | SVG if possible, else PNG or lossless WebP | Lossless |
| Image with transparency | PNG, WebP or AVIF | Either |
Step by step
- Start from the original. Every lossy save loses a little more. Never compress a file that has already been compressed several times if you have the original.
- Resize first. This is where most of the saving is. A 12-megapixel photo (4032 × 3024) shown on a web page at 1600 pixels wide has more than six times the pixels it needs. Pick the largest size it will really be displayed at, doubled for high-density screens if it's for a website, and resize to that.
- Choose the format from the table above. For photos going to someone else, JPEG opens everywhere. For your own website, WebP or AVIF with a fallback is smaller; see PNG vs WebP for when each wins.
- Set the quality. Start at 80 for JPEG or WebP. There's no universal scale, so 80 in one app isn't 80 in another; judge by eye.
- Compare at 100% zoom. Look at edges, skies, skin and text. Typical artifacts are blocky 8×8 squares and halos around edges (JPEG), or smeared fine texture (WebP/AVIF at low settings).
- Lower the quality until you see a difference, then step back up by 5 or 10.
- Strip metadata you don't need: GPS location, camera details, edit history, embedded thumbnails. Our EXIF remover does this in the browser without uploading the file.
- Save as a new file. Keep the original untouched.
If you'd rather not juggle settings, our free image compressor does the same steps in the browser.
How much each step saves
Rough, honest expectations for a typical phone photo:
| Step | Typical effect |
|---|---|
| Resize 4032 px → 2048 px wide | About a quarter of the pixels, often the biggest saving |
| JPEG quality 100 → 80 | Large reduction, usually invisible |
| JPEG → lossy WebP | Google reports 25–34% smaller at equal SSIM quality |
| PNG → lossless WebP | Google reports about 26% smaller |
| Remove EXIF | Small: kilobytes, not megabytes |
| Re-saving an already compressed JPEG | Little saving, some extra loss |
Two things don't help: zipping a JPEG (it's already compressed) and saving a JPEG as PNG (the file gets bigger and the earlier loss stays).
Built-in tools that already do this
You don't always need an extra app.
- Mac, Preview: open the image, choose Tools > Adjust Size to resize, then File > Export, pick JPEG or HEIC and move the Quality slider. The export window shows the resulting file size.
- Mac, Finder: Control-click an image, choose Quick Actions > Convert Image, then pick a format and a smaller size.
- Windows, Photos: open the image, use the ... menu and choose Resize image, then pick a size and quality.
- iPhone: Mail offers to scale attached photos (Small, Medium, Large). The Shortcuts app's Resize Image and Convert Image actions can resize and set JPEG quality for a batch.
- Android: many gallery apps include resize in their edit tools; options vary by manufacturer.
Sending by email? Email attachment size limits lists the caps per provider and why files grow by a third in transit.
Metadata: small bytes, big privacy
Removing metadata won't turn 4 MB into 400 KB. EXIF in a JPEG is capped at 64 KB by the format, and most photos carry far less, though an embedded preview thumbnail or a color profile adds some. On a small web image that can still be a noticeable share of the file.
The bigger reason is privacy. A photo can carry GPS coordinates accurate to a few meters, the date and time, and your phone model. Check what a file contains with the guide on how to check photo metadata before you post or send it.
One catch: stripping everything also removes the color profile in some tools. Photos from recent phones often use the Display P3 color space; without the profile, colors can look slightly duller. Good tools convert to sRGB or keep the profile.
Common mistakes
- Compressing instead of resizing. Crushing a 4000-pixel image to quality 40 looks worse than resizing it to 1600 pixels at quality 80, and is often bigger.
- Using PNG for photos. PNG is lossless, so a photo saved as PNG is often several times larger than a good JPEG.
- Using JPEG for screenshots. Text gets fuzzy halos. Use PNG or lossless WebP.
- Compressing again and again. Each lossy save adds artifacts. Always go back to the original.
- Trusting the number alone. Quality 80 means different things in different apps. Look at the result.
Keeping the originals safe
Compression is for the copies you share. The originals are worth keeping intact, and some of them, such as ID scans, medical photos and documents, are worth keeping private too.
sigil. keeps photos in an encrypted vault on your phone with a 256-bit key that only the sign you draw opens. It strips EXIF and location when you import a photo and again when you export one, so a shared copy doesn't carry your location, and it warns you that an exported copy is no longer encrypted. Photos taken with its private camera never touch the Camera Roll. It's local-first with no cloud backup yet, so keep your own backup.
Bottom line
Resize to the real display size, pick the format by image type, start at quality 80 and judge at 100% zoom. Use lossless only where exact pixels matter, such as screenshots and graphics. Strip metadata for privacy more than for bytes, and always compress a copy, never the original.
Sources
Frequently asked questions
Can you compress an image without losing any quality?
Yes, with lossless compression such as optimized PNG or lossless WebP, but the savings are modest. Big reductions come from lossy compression tuned so the loss isn't visible, and from resizing.
What JPEG quality setting should I use?
Quality scales differ between apps, but on the common 0–100 scale, 75 to 85 is a good starting point for photos. Compare the result at 100% zoom and go lower until you see artifacts, then step back up.
Does resizing reduce quality?
It reduces resolution, which is only a loss if the image will be shown or printed larger than the new size. A photo shown at 1200 pixels wide gains nothing from being 4000 pixels wide.
Is WebP or AVIF better than JPEG?
Both usually give smaller files at the same visual quality. Google reports lossy WebP is 25–34% smaller than JPEG at equal SSIM. JPEG is still the safest choice when you don't know what the recipient will open it with.
Does removing metadata make an image smaller?
A little. EXIF data is typically a few to a few dozen kilobytes, more if there's an embedded thumbnail or color profile. It matters most for small web images and for privacy.