Lossless Image Compression
Get lossless image compression in your browser, with the quality set high so the difference stays invisible. Shrink JPG and PNG files while keeping them crisp, all privately, with no upload.
Unlimited images, No File Size Limits.
Why use CompressImage.io to compress images losslessly?
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No Limits
As the compression is happening in the Browser, there are no limits on how many images you can convert or what size of image you can convert.
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100% Private
Since no images are sent to any servers, your images are totally safe and private as no one else can see your images.
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Low Carbon Footprint
Since no servers are involved in the compression process, zero extra electricity is used, hence no carbon emitted.
How to Lossless Compression
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Add your images
Drag your JPG and PNG images onto the tool or click Select Files. This page starts with quality set high for near-lossless results.
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Each image compresses at high quality
Your browser compresses every image at a high quality setting, so detail is kept. Nothing is uploaded to any server.
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Download your images
Save each image on its own or all of them as a ZIP. Nudge the quality slider in Settings if you want to trade a little fidelity for a smaller file.
What lossless image compression actually does
Lossless image compression makes a file smaller without throwing away any image data, so the result is pixel-identical to the original. The savings come from packing the same information more efficiently, not from blurring detail. PNG is the classic lossless format, and you get true zero-loss output by saving as PNG at full quality.
This page keeps the quality slider high, so JPG and PNG files shrink while the result stays visually identical to the source. That near-lossless setting is the sweet spot for design assets, print-bound photos, and any image you plan to edit again.
Lossless or lossy: which do you need?
Use lossless, or near-lossless, compression when every pixel matters:
- Logos, icons, and line art
- Screenshots and images that contain text
- Master files you will re-edit or send to print
Lossy compression discards detail the eye does not easily catch, which reaches far smaller files. It is the right call for photographs that are going straight to final display.
Getting the smallest lossless file
For guaranteed zero-loss output, use PNG at maximum quality. For the smallest near-lossless web files, try converting to WebP, which has a lossless mode of its own. To run a whole site’s worth of images through the same settings, use the image optimizer.
Frequently Asked Questions
Is this true lossless compression?
The tool maximizes quality by keeping the slider high, so the result is visually indistinguishable from the original, which is near-lossless. For genuinely zero-loss output, save as PNG with the quality slider at 100%, since PNG itself is a lossless format.
What is the difference between lossy and lossless compression?
Lossless compression reduces file size without discarding any image data, so the result is pixel-identical to the original. Lossy compression removes detail the eye barely notices to reach much smaller files. PNG is lossless and JPEG is lossy.
Will my images look exactly the same?
With the quality slider set high, the difference is invisible to the human eye. For pixel-perfect, zero-loss results, use a PNG at 100% quality.
Are my files uploaded anywhere?
No. All compression happens locally in your browser. Your images never leave your device, so the tool is private and works offline.
When should I use lossless instead of lossy?
Use lossless or high-quality compression for logos, line art, screenshots, images with text, and anything you will edit again. Use lossy for photographs you are delivering for final display, where a smaller file matters more than perfect pixels.