Image Compressor
Cut image file size by 50–90% with a quality slider you control and a before-and-after preview — all inside your browser, with no upload.
Original
Compressed
About the Image Compressor
Images are almost always the heaviest thing on a web page. A single unoptimised photo straight from a phone camera can be four megabytes, which is more than the HTML, CSS, JavaScript and fonts of an entire well-built site combined. That weight lands directly on Largest Contentful Paint, the Core Web Vitals metric that measures when the main content of a page becomes visible, and it is felt hardest by exactly the visitors you can least afford to lose: people on mobile data with an older device.
Compression works by discarding information the human eye is poor at noticing. JPEG and WebP encoders throw away high-frequency detail and colour precision in areas where the loss is hard to see. The trick is finding the point where the file is dramatically smaller and the picture still looks right — and that point depends on the image. A photograph of foliage tolerates aggressive compression; a screenshot with fine text or a logo with flat colour shows artefacts almost immediately.
That is why this compressor gives you a slider and a live preview instead of a single “optimise” button. You move the quality control, watch the file size and the picture change together, and stop at the setting that looks right to you. The work happens on an HTML5 canvas in your own browser, so a twelve megabyte photo compresses as quickly on a slow connection as on a fast one — because nothing is ever transmitted.
How to use it
- Select your imageDrag a file onto the drop zone or click to browse. JPG, PNG, WebP, GIF and BMP inputs are all accepted.
- Choose an output formatKeep the original format, or switch to WebP, which typically saves another 25–35% at matching visual quality.
- Move the quality sliderStart around 75%. The output size updates live so you can see the trade-off as you drag.
- Compare the previewThe original and compressed versions are shown together with both file sizes and the percentage saved.
- Optionally cap the dimensionsSetting a maximum width is often the single biggest saving — a 4000px photo displayed at 800px is wasting three quarters of its pixels.
- Download the resultSave the compressed file. The original on your device is never modified.
Features
- Live quality sliderSee file size and image quality change together instead of guessing at a preset.
- Format switchingCompress to JPEG or WebP, or keep PNG for images that need transparency.
- Optional resizingCap the longest edge during compression — usually a bigger saving than quality alone.
- Side-by-side previewOriginal and compressed shown together with both sizes and the exact percentage saved.
- No upload, no limitFiles are processed on a canvas in your browser, so there is no size cap, queue or watermark.
- Batch friendlyBecause there is no upload wait, the next image starts the instant you select it.
Who uses this tool
- Website ownersGet image weight down before publishing to improve Largest Contentful Paint and overall page speed scores.
- Bloggers and WordPress usersCompress featured images before upload so the media library stays small and pages load quickly.
- E-commerce sellersMeet marketplace file size limits for product photos without losing the detail buyers zoom into.
- Anyone sending filesFit photos under an email attachment limit or a form's upload cap without cropping anything out.
Tips worth knowing
- Resize before you compress. Reducing a 4000px wide photo to the 1200px your layout actually displays typically saves more than any quality setting.
- WebP is supported by every current browser and usually beats JPEG by 25–35% at the same perceived quality — it is the default worth choosing.
- Screenshots, logos and line art with flat colour should stay PNG. Lossy compression puts visible fringing around sharp edges and text.
Frequently asked questions
Does compressing an image reduce its quality?
Lossy compression always discards some data, but between about 70% and 85% quality the loss is very hard to see on a photograph while the file typically shrinks by 60–80%. The live preview exists so you can judge that trade-off on your own image rather than trusting a number.
Are my images uploaded to a server?
No. The file is read with the browser's FileReader, drawn to a canvas and re-encoded locally. You can open your browser's network panel and watch: no request carrying image data is made. This makes the tool safe for client work, documents and personal photos.
What is the best format for the web?
WebP for photographs and most graphics — it is supported everywhere current and is meaningfully smaller than JPEG at the same quality. Keep PNG when you need transparency or the image is text, a logo or a screenshot with hard edges.
Why did my PNG barely shrink?
PNG is a lossless format, so quality settings have little effect on it. To make a PNG substantially smaller you generally need to either reduce its dimensions or convert it to JPEG or WebP — both offered here.
Is there a maximum file size?
No fixed limit. The practical ceiling is your device's available memory, since the image is decoded into a canvas. Files up to around 30 megapixels are comfortable on a typical modern phone or laptop.
Does compression remove EXIF data?
Yes. Re-encoding through a canvas drops EXIF metadata, including GPS coordinates, camera model and timestamps. That is a privacy benefit for images you are about to publish, but do keep your original if you want that data preserved.