Image Compressor
Shrink images by quality or to fit under a specific size limit. Every image is compressed on your device, so nothing is uploaded and there is no waiting.
Related tools
How to compress an image
- Add your images. Drag them onto the box above or click to browse. Add as many as you like.
- Choose how to compress. By quality lets you set a level directly. By target size lets you name a maximum file size and works out the quality for you.
- Pick an output format, or leave it on the default, which keeps JPEG and WebP as they are and converts PNG, GIF and BMP to a format that actually compresses.
- Compress and download. Each row shows the before and after size with the percentage saved. Save images individually or download the batch as a ZIP.
Nothing is uploaded at any point.
When you would need this
Getting under an upload limit. Job application portals, government forms, insurance claims and marketplace listings routinely cap uploads at 1MB or 2MB, and a photo from a modern phone is several times that. Target size mode exists specifically for this.
Making a website faster. Images are usually the largest thing on a web page and the main reason pages feel slow on mobile. Compressing them is the single highest-impact performance change available on most sites, and it directly affects Core Web Vitals.
Emailing photos. Mail providers commonly limit attachments to 20MB or 25MB. A dozen full-resolution phone photos will exceed that; compressed, they will not.
Reclaiming storage. A folder of holiday photos can often be reduced by seventy percent with no visible difference at normal viewing size.
Speeding up a document. Images embedded in a PDF or presentation carry their full weight into the file. Compressing before inserting keeps the result manageable.
What lossy compression actually throws away
Understanding the mechanism makes the quality slider much easier to judge. Lossy compression does not shrink an image by storing the same picture more efficiently — it works by discarding information the human eye is least likely to miss, and the quality setting controls how much it discards.
Two properties of human vision are being exploited. First, we are far more sensitive to brightness than to colour, so colour information is stored at reduced resolution while brightness is kept intact. Second, we notice large shapes much more than fine texture, so the encoder divides the image into small blocks and progressively drops the finest detail within each one.
This is why compression artefacts appear where they do. Blockiness in smooth areas such as skies is the block structure becoming visible once too much detail has been removed. Coloured fringing around text and sharp edges is the reduced colour resolution showing up exactly where a hard boundary needs precision. Banding in gradients is the same problem in a different guise.
It also explains why content matters more than any setting. A busy photograph of foliage hides artefacts easily, because there was fine texture everywhere to begin with. A screenshot of text, a logo on flat colour, or a photograph of a clear sky has almost nothing to hide behind, and the same quality setting that looks perfect on one will look poor on the other.
Tips for compressing well
Start at 75% and judge by eye. There is no universally correct setting, because it depends on the image and on how it will be viewed. 75% is a good default for photographs. Compare the result at full size before committing to anything lower — a setting that looks fine in a thumbnail can fall apart when someone opens the image.
Resize before you compress. If your 4000-pixel-wide photo will be displayed at 800 pixels, resizing it is a far bigger saving than any quality setting, and it costs no visible quality at all. Use the image resizer first, then compress. Doing both usually beats aggressive compression alone by a wide margin.
Never compress twice. Each lossy pass discards more detail, and the damage accumulates — artefacts from the first pass get treated as real detail by the second. Always compress from your original, not from a file you compressed earlier.
Match format to content. Photographs belong in JPEG, WebP or AVIF. Screenshots, logos, diagrams and anything with text or flat colour belong in PNG or lossless WebP, where sharp edges stay sharp. Compressing a screenshot as a low-quality JPEG produces visible fringing around every letter.
Use WebP unless you have a reason not to. It is supported by every current browser, handles both photographic and graphic content, supports transparency, and is meaningfully smaller than JPEG at the same visual quality. Keep JPEG when a file has to open in older software or be accepted by a system you do not control.
Watch out for gradients. Skies, sunsets and subtle shading are where lossy compression shows first, as visible banding. Images with large smooth areas need a higher quality setting than busy, detailed ones.
Limits and requirements
Compression is irreversible. Lossy compression discards data permanently. Keep your originals.
PNG will not shrink much. PNG is lossless by design. Real savings come from converting photographic PNGs to JPEG, WebP or AVIF, which the default setting does.
Metadata is not preserved. Re-encoding drops EXIF, including camera settings, timestamps and GPS coordinates. Usually a benefit; occasionally not.
AVIF output depends on your browser. Not every browser can encode AVIF, and the option is hidden where it is unavailable rather than silently producing a mislabelled file. AVIF is also slower to encode than the alternatives.
Memory is the constraint. Every image is decoded to raw pixels, which takes roughly four bytes per pixel — a 50-megapixel photo occupies around 200MB while being processed. Large batches of high-resolution images are best done in smaller groups on a phone.
Animated GIFs lose animation. Only the first frame is processed. Converting animation is a different job.
Privacy: how this tool handles your images
Your images never leave your device. When you add a file, your browser decodes it into memory, re-encodes it at the settings you chose, and hands the result straight back. There is no upload, no server-side processing and no copy on our infrastructure — because no infrastructure is involved.
This matters more for images than for almost anything else, because of what people compress. Photos of children. Pictures of a home being listed for sale. Photographed documents. Medical images. Screenshots containing account details. These get fed into free compression sites constantly, and the ordinary version of that transaction involves handing a full-resolution copy, GPS coordinates included, to a company nobody has heard of.
You can check this rather than trusting it. Open your browser's developer tools, switch to the Network tab, and compress an image — nothing carries your file. Or load this page, disconnect from the internet, and compress anyway. It still works, because everything needed is already running on your machine.
Frequently asked questions
Are my images uploaded to a server?
No. Images are decoded and re-encoded in your browser using the canvas and codec support built into the browser itself. Nothing is transmitted or stored by us. You can verify this by opening your browser's developer tools, switching to the Network tab, and compressing an image — no request carries your file. This matters for photos in particular, which often contain location metadata and personal content.
How much quality will I actually lose?
At 75% quality most photographs are indistinguishable from the original at normal viewing size while being sixty to eighty percent smaller. Between 50% and 70% the difference becomes visible if you look closely at fine detail and smooth gradients such as skies. Below 50% you will see blocky artefacts. Screenshots, line art and text-heavy images degrade faster than photographs and are usually better served by PNG or WebP than by aggressive JPEG compression.
What does target size mode do?
You name a maximum file size and the tool works out the quality setting that fits under it, by encoding the image repeatedly and narrowing in on the answer. This is what you want when an upload form insists on a limit like 2MB. If the target is too small to reach even at minimum quality, you get the smallest achievable version plus a note saying the target was not met, rather than a silent failure.
Why did my PNG get bigger instead of smaller?
PNG is lossless, so it cannot be compressed by discarding detail the way JPEG can. Re-encoding a PNG as PNG usually achieves little and can occasionally produce a slightly larger file. If your PNG is a photograph, convert it to JPEG or WebP — that is where the large saving lives, often ninety percent or more. The default setting does this automatically. If your PNG is a screenshot, logo or line art, keep it as PNG or use WebP, which handles both cases well.
Is compression reversible?
No. Lossy compression permanently discards image data, and no tool can restore it. Always keep your originals, especially for photographs you might want to print or edit later. Compressing an already-compressed image degrades it further, so start from the highest-quality source you have rather than re-compressing a file you compressed before.
Can I compress several images at once?
Yes. Add as many as you like and they are processed one after another with the same settings. Individual results can be saved separately, or you can download the whole batch as a single ZIP. Because processing happens on your device, a large batch is limited only by your device's speed and memory rather than by an upload queue.
Does compressing remove EXIF and location data?
Yes, as a side effect. The image is decoded to raw pixels and re-encoded, which does not carry metadata across — so the output has no EXIF, no GPS coordinates and no camera information. That is usually welcome if you are posting the image publicly. If you need to keep capture details, keep your original file.
Which format compresses best?
For photographs, AVIF is smallest, WebP is close behind and much more widely supported, and JPEG is the safest universal choice. WebP is typically twenty-five to thirty-five percent smaller than JPEG at matching quality, and AVIF can halve it. For screenshots and graphics with flat colour and sharp edges, PNG or lossless WebP look better than any JPEG at a comparable size.