How to compress a JPG without visible quality loss
JPG (also written JPEG) is the format most cameras and phones use for photos, and it is brilliant at packing rich, colourful scenes into a modest file. The catch is that a straight-out-of-camera JPEG is rarely optimised: it often carries far more data than a website or an email actually needs. The goal when you compress a JPG is not to strip out detail you can see; it is to remove the redundant data your eyes were never going to notice in the first place.
Our tool does this in two complementary ways. First, it can re-encode your photo to an optimised WebP version at a sensible quality level, which usually beats the original JPG for the same visual result. Second, it can resize very large images down to the dimensions you truly need. To try it, simply open the compressor, drop your photos in, and compare the sizes it produces before you download.
Why a JPG is already lossy
Understanding one fact makes JPG compression far less mysterious: the format is lossy by design. When your camera saved the photo, it already threw away subtle information to keep the file small; that is how JPG works. So a JPEG is not a pristine master; it is a compressed approximation. This is good news, because it means re-compressing sensibly does not ruin some perfect original; there was never a lossless original to protect. The trick is choosing a quality setting that stays above the point where compression artefacts (blocky skies, haloed edges) become visible.
At around quality 80, the difference is effectively invisible for most photographs, yet the saving is substantial. That is exactly the lossy setting our compressor produces automatically, alongside a lossless copy, so you can judge both with your own eyes rather than trusting a slider.
Typical size savings by image type
Results vary with the content of the picture, but the table below shows the ballpark reductions people usually see when a JPG is converted to optimised WebP at a good quality level.
| Image type | Typical JPG source | Saving as optimised WebP |
|---|---|---|
| Detailed landscape or travel photo | 3–6 MB | 25–45% |
| Portrait or product shot | 1–3 MB | 35–60% |
| Screenshot saved as JPG | 400 KB–1 MB | 50–75% |
| Flat graphic or simple background | 200–600 KB | 60–80% |
The broad range, roughly 25% to 80%, reflects how much redundant data a photo contains. Busy, noisy images compress less; smooth, flat ones compress more.
When to keep JPG and when to move to WebP
JPG remains a safe, universal choice. Every browser, email client, printer and photo frame understands it, so if maximum compatibility matters (a print order, a client who insists on JPEG, an old device), keep the JPG. For anything destined for a modern website or app, however, WebP is usually the better pick: smaller files at the same quality, faster page loads, and support across every current browser. If you are weighing the options, our WebP vs JPG vs PNG comparison lays out the trade-offs side by side.
Resizing large camera photos for web and email
Modern phones capture 12, 48 or even 100 megapixels. That detail is wonderful for printing, but a web page or an email attachment never displays it; the extra pixels are simply discarded by the screen. Sending a 6 MB, 6000-pixel-wide photo when 1500 pixels would look identical wastes bandwidth and clogs inboxes. The compressor offers four sizes, Original, Small (−25%), Smaller (−50%) and Smallest (−75%), with the aspect ratio preserved and high-quality resampling, so you can shrink dimensions and file size together in one step.
Batch compressing lots of JPGs at once
If you have a whole folder to get through, drop them all in together. The tool compresses every JPG in the batch, shows you the before-and-after sizes for each, and lets you grab everything in a single Download-All ZIP. Because the work happens on your own machine, a hundred photos are handled just as privately as one: nothing is uploaded, there is no queue, and there is no limit tied to an account, because there is no account. It is free forever, with no watermarks, and made in the UK.
Frequently asked questions
Will compressing a JPG make it look worse?
At sensible settings, no. Because JPG is already lossy, a well-chosen quality level (around 80) removes only data you cannot perceive whilst cutting the file size sharply. Converting to optimised WebP typically shrinks it further at the same visual quality, and you can always compare both versions before downloading.
How much smaller can a JPG get?
Converting a typical JPEG to optimised WebP commonly saves between 25% and 80%. Large camera photos that you also resize for the web often shrink even more, because the surplus pixels are removed before encoding.
Are my JPG files uploaded to a server?
No. Every image is processed inside your browser using the real libwebp encoder compiled to WebAssembly, so your photos never leave your device. That keeps the tool completely private and lets it work even on a slow or offline connection.