Free · No sign-up · Runs in your browser
Compress an image to 20KB, 50KB or 100KB, free
Shrink JPG and PNG file sizes for faster uploads and smaller attachments, or aim for an exact size like 20 KB, 50 KB or 100 KB when a form sets a limit. Batch process as many as you like, without a single file leaving your device.
Not uploaded — nobody sees it Hit an exact size in KB No watermark, ever No subscription or account
Or aim for a size (optional)
Each image is saved at the best quality that fits. If quality alone isn’t enough, its width and height are reduced too.
Preparing…
Your files are never uploaded — they’re processed right here in this browser tab, on your device. They never reach a server, so we never see them, copy them or keep them.
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Compress image: quick facts
Shrink JPG and PNG photos, or hit an exact size like 50KB, in your browser.
Updated
- Price
- Free. No sign-up, no watermark.
- Targets
- Light, Medium or Strong, or aim for 20KB, 50KB, 100KB, 200KB, 500KB, 1MB or any size.
- Typical saving
- Medium usually cuts photo file sizes by 60 to 80%.
- Output
- JPG (PNGs are re-saved as JPG, so transparency becomes white). Batches download as a .zip.
- Photo details
- Date, camera and GPS location are removed from compressed images.
- Privacy
- Your images are compressed in your browser and never uploaded.
How it works
How to compress JPG and PNG images
Each image is re-saved as a JPG at the strength you pick (Light, Medium or Strong) with its width and height unchanged. Or set a target size and Altto searches for the best quality that fits, reducing the dimensions only if it has to.
- 01
Add your images
Drop in one or more JPG or PNG files.
- 02
Pick a strength or a size
Light, Medium or Strong, or a target such as 50 KB or 100 KB.
- 03
Save your images
One downloads directly; several come back as a .zip.
Tips
Tips for smaller images that still look good
Compression does its best work on photos. These habits get you the smallest file you’re happy with.
- Resize first if the photo is hugeCompression keeps every pixel, and a phone photo has far more than most screens or upload forms need. Shrink it with Image Resize first, then compress the resized copy; together they usually cut the file much further than compression alone.
- Start at Medium and adjustMedium is selected when the page opens and suits most photos. Check the result at the size people will actually see it: if it looks soft, go back to Light; if the file is still too big, try Strong.
- If an image comes back unchangedThat means saving it again would have made it bigger, which happens with JPGs that were compressed hard before and with small, simple graphics. You can try Strong, but if it still comes back unchanged, reducing its width and height is the surer way to get a smaller file.
- Keep transparent logos as PNGA compressed PNG comes back as a JPG, so a transparent background turns white. To make a logo or cut-out lighter without losing its transparency, reduce its width and height with Image Resize instead, which keeps PNGs as PNGs.
Like every Altto tool, this runs on your device — nothing you add is uploaded. How Altto works
10:1
is roughly how far JPG can shrink a typical photo with little visible loss. Screenshots, logos and images that are already compressed have much less to give.
Size targets
Which image size do I need?
Upload forms often set a limit in KB. Here’s what each target typically means for a photo.
| Target | Often asked for | What to expect |
|---|---|---|
| 20 KB | Signatures and passport-style photos on exam, job and visa forms | Small in pixels (around 300–500 wide), fine on screen |
| 50 KB | Profile photos and ID photos on application forms | Clear on screen, usually reduced to 600–900 pixels wide |
| 100 KB | Most online forms, forums and email-friendly images | Good quality at around 1,000–1,400 pixels wide |
| 200 KB | Job portals, website images, listings | Very good quality, often full width for screens |
| 500 KB – 1 MB | Email attachments, marketplace listings | Little or no visible change for most photos |
FAQ
Frequently asked questions
What each strength does, and where compression runs out. For compressing versus resizing, see our guide on how to resize an image. Shrinking a photo for a UK passport application? Check it against the rules with our passport photo checker.
Why does the compressed file come back as JPG?
JPG’s quality setting is what actually shrinks a photo’s file size. If you upload a PNG, it’s re-encoded as a high-quality JPG so the size reduction is real — note this does flatten any transparency to white.
How much smaller will my image get?
It depends on the image, but Medium typically cuts photo file sizes by 60-80%. Try Strong if you need the smallest possible file and don’t mind a bit more softness.
Will I notice the quality loss?
At Light or Medium, most people can’t tell the difference at normal viewing sizes. Strong trades more visible quality for a smaller file.
Can I compress several images at once?
Yes — add as many images as you like. One downloads directly; more than one comes back as a .zip.
Can I compress to an exact size, like under 1 MB?
Yes. Under “Or aim for a size”, pick 20 KB, 50 KB, 100 KB, 200 KB, 500 KB or 1 MB, or choose Other and type any size. Each image is saved as a JPG at the highest quality that fits. If even a low quality setting can’t get it small enough, the width and height are reduced step by step until it fits, and the page tells you the final size and dimensions.
How do I reduce a photo to 50 KB or 20 KB?
Add the photo, choose 50 KB or 20 KB and press the button. A phone photo is usually several megabytes, so to reach 20 KB it will also be made smaller in pixels, typically to a few hundred pixels across. That’s normal: it’s what forms asking for a 20 KB passport-style photo or signature expect.
Why did my image get smaller in width and height?
Quality can only take a file so far before a photo looks blocky. Below that point, reducing the number of pixels is the better trade, so the tool shrinks the dimensions step by step instead. If a form also asks for exact dimensions, set those first with Image Resize, then compress here.
Does it remove the photo’s location and camera details?
Yes, for every image it compresses. The new JPG doesn’t keep the details a phone or camera stores inside a photo, such as the date taken, the camera model and GPS location. An image that was already as small as it can go comes back unchanged, though, details and all, so check what the page says before you post it publicly.
What happens if my image can’t get any smaller?
You get the original back, unchanged. A JPG that’s already been compressed hard, or a small, simple graphic like a logo, can come out bigger when it’s saved again, so the tool compares the two sizes and never hands you the larger file. The page tells you when this happens, and a PNG that’s kept stays a PNG, transparency and all.
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