Image Compressor
Make images dramatically smaller without making them look worse.
Related tools
What is the Image Compressor?
The Image Compressor shrinks JPG, PNG and WebP files by re-encoding them at a lower quality setting, cutting file size dramatically with little to no visible difference at normal viewing sizes. A 4 MB JPEG straight off a phone camera typically lands around 400 KB at a quality setting of 0.7, with no visible change when viewed at normal screen size. Push it lower than about 0.5 and you start to see blocking artefacts in flat areas like skies and shadows. Everything runs in your browser using the Canvas API, so your photos are never uploaded anywhere — you drag a file in, adjust the quality slider, and download the result.
Compression and resizing solve different problems. Compression reduces file size at the same pixel dimensions by discarding data the format allows you to discard — this tool does that. If your image is also larger than you need in width and height, resizing it first will shrink the file further than compression alone.
Why use a free image compressor?
Dramatic size reduction, minimal visible loss
JPEGs typically compress 70–90% smaller at quality 0.7–0.8 with no difference visible at normal viewing size. The exact number depends on the image — busy, detailed photos compress less than simple graphics.
Works on JPG, PNG and WebP
Each format compresses differently — JPEG and WebP support adjustable lossy compression, PNG compresses losslessly with a smaller available range.
Quality slider, not a fixed preset
See the file size and a live preview update as you move the slider, so you can find the point where size drops but quality doesn't, for your specific image.
Never uploaded
Compression runs entirely in your browser via the Canvas API. Your original file never reaches a server, which matters for anything containing personal photos or confidential documents.
No file limit, no watermark
Compress as many images as you need, at full resolution, with no branding added to the output.
How do you use the Image Compressor?
- 1
Upload your image
Drag and drop a JPG, PNG or WebP file, or click to browse. The file loads directly into your browser.
- 2
Adjust the quality slider
Move the slider and watch the estimated output size update. Higher quality keeps more detail; lower quality produces a smaller file.
- 3
Compare original and compressed
Check the preview against the original at normal viewing size — most compression artefacts only become visible when you zoom in.
- 4
Download the result
Save the compressed file. It keeps the same dimensions as the original unless you also resize it.
How is image compressor calculated?
Reduction % = (original size − compressed size) ÷ original size × 100Where:
- original size
- File size of the image before compression, in bytes
- compressed size
- File size after re-encoding at the chosen quality setting
- quality (0–1)
- The setting passed to the encoder — lower values discard more data in exchange for a smaller file
The simple version
Lossy formats like JPEG and WebP store an approximation of the image rather than every pixel exactly. The quality setting controls how much approximation is allowed: at 1.0 (or 100%) almost nothing is discarded and the file stays large; at 0.5 a lot is discarded and the file shrinks a lot, but you start to see it in flat, low-detail areas first.
What does it look like in practice?
Phone photo, moderate compression
Input
4.1 MB JPEG, 4032×3024, quality set to 0.7
Result
~410 KB, same dimensions, no visible difference at normal size
This is the typical result for a well-lit photo with natural detail like foliage or fabric, which hides compression artefacts well.
Screenshot with flat colour and text
Input
1.8 MB PNG screenshot, quality set to 0.6 after converting to JPEG
Result
~90 KB, but visible blocking around text edges
Flat colour areas and sharp text edges show JPEG artefacts more readily than photos do — PNG or WebP lossless mode usually gives a cleaner result for screenshots and graphics with text.
Aggressive compression
Input
Same 4.1 MB JPEG, quality set to 0.3
Result
~180 KB, with visible blocking in the sky and smoother gradients
Below roughly 0.5, artefacts become visible in flat areas even at normal viewing size — this setting only makes sense when file size matters more than visual quality, such as a thumbnail.
How accurate is it?
Compression happens through the browser's native Canvas re-encoding, using the same underlying codecs as desktop image editors. The output size shown is the actual size of the file you download, not an estimate.
- Results vary by image content, not just the quality number — a photo with lots of fine detail (grass, hair, fabric texture) compresses less than a smooth gradient or a simple graphic at the same quality setting.
- PNG compression is lossless, so the size reduction available is smaller and more limited than JPEG or WebP, which allow you to trade quality for size.
- Very large source files are limited by your device's available memory rather than by this tool, since everything processes locally in your browser.
What should you know before using it?
How the three supported formats compress, and when to use each:
| Format | Compression behaviour |
|---|---|
| JPEG | Lossy, adjustable quality. Best for photos with natural detail. Does not support transparency. |
| PNG | Lossless. Smaller size range than JPEG, but keeps every pixel exact — best for screenshots, logos and images needing transparency. |
| WebP | Supports both lossy and lossless modes, usually producing smaller files than JPEG or PNG at equivalent visual quality, with transparency support. Not accepted by every older application. |
Which tools relate to the image compressor?
The image compressor is one of 31 image tools on this site. These are the ones most often used alongside it — either because they handle the next step in the same job, or because they answer a question this tool raises.
Image Resizer
Reduce pixel dimensions before compressing — a 4000px-wide photo displayed at 800px wastes both bandwidth and storage that resizing recovers on top of compression.
Compress JPEG
The JPEG-only version of this tool, for when you already know your input format and want a narrower, faster workflow.
PNG to WebP
Convert to WebP first if your target platform supports it — WebP often produces a smaller file than a compressed PNG at similar visual quality.
HEIC to JPG Converter
iPhone photos save as HEIC by default, which many platforms cannot open. Convert to JPEG first, then compress.
When should you use a image compressor?
Because the image compressor runs entirely in your browser, it suits work you would not want to hand to a third-party server — client files, unpublished drafts, anything under an NDA. These are the situations people reach for it in most often.
Website performance
Oversized images are the single most common cause of a slow-loading page. Compressing hero images and product photos directly improves load time and Core Web Vitals.
Email attachments
Many mail providers cap attachment size — compressing a batch of photos can be the difference between one email and a shared-drive link.
Marketplace and social uploads
Platforms with upload size limits, or that recompress large images themselves and lose more quality in the process, benefit from a smaller, deliberately compressed file uploaded in the first place.
Storage and backup
Compressing a large photo library before archiving it can cut storage use substantially, particularly for phone photos that are rarely viewed at full resolution.
Frequently asked questions
How much can I compress an image without losing visible quality?
What is the difference between compressing and resizing an image?
Does compressing a PNG work as well as compressing a JPEG?
Is my image uploaded to a server when I compress it?
Why does my compressed image still look blurry?
What image format compresses the smallest?
Is the image compressor safe to use?
This tool runs entirely inside your browser. Your text, files and settings are processed on your own device and are never uploaded to our servers — there is nothing for us to store, log or leak. You can confirm it yourself: open your browser DevTools, switch to the Network tab, and use the tool. You will not see an upload request. It also means the tool keeps working if your connection drops mid-task.
Where do these figures come from?
Every method, threshold and standard this page relies on, with a link to the document that defines it. Check them — a tool that will not show its sources is asking you to take its word for it.
- 1Information technology — Digital compression and coding of continuous-tone still images: Requirements and guidelines
ITU-T Recommendation T.81 / ISO/IEC 10918-1 · 1992
Supports: The lossy, adjustable-quality DCT compression described for JPEG.
- 2Portable Network Graphics (PNG) Specification (Third Edition)
W3C · 2003
Supports: The description of PNG as lossless with a smaller available compression range than JPEG or WebP.
- 3WebP Compression Study
Google Developers
Supports: The claim that WebP usually produces smaller files than JPEG or PNG at equivalent visual quality.
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