How to compress an image without losing quality
Compressing an image means making the file smaller while keeping the picture itself looking about the same. The trick is knowing where you can throw information away without anyone noticing. Most photos have far more data than the eye needs — a well-compressed JPEG at 75% quality is usually indistinguishable from the original, but can be 80 to 90 percent smaller.
Three controls decide how small your file gets: the quality setting, the maximum dimensions, and the output format. Let's look at each.
Quality setting
Quality is a number between 0 and 100 that tells the encoder how aggressively to throw out detail. For web images, 70–80 is the sweet spot. Below 50, you start to see blockiness and fuzzy edges. Above 90, file savings drop off — you're paying a lot of bytes for detail your eye can't see.
Maximum dimensions
A photo straight from a modern phone camera is often 4000 pixels wide or more. Almost no website, email, or social platform actually displays an image that big. Capping the longest side at 2000 pixels typically cuts file size in half again, on top of the quality reduction, without any visible loss unless you're printing large.
Output format
If the image is a photo, JPEG is almost always smallest. If it has sharp graphics, text, or transparency, PNG or WebP is safer. WebP tends to be 25–35% smaller than JPEG at the same quality and is now supported everywhere — it's the best choice for most websites in 2026.
When should I use PNG vs JPEG vs WebP?
- JPEG — photos, realistic images, anything with gradients and natural colour.
- PNG — screenshots, logos, illustrations, images with transparency.
- WebP — anything where the destination (website, CMS, app) supports it. Modern browsers all do.
Frequently asked
Are my images uploaded anywhere?
No. This tool is a single HTML page that loads JavaScript into your browser. The compression code runs on your own device using your own CPU. Your image files never leave your computer. You can even turn off your internet connection after the page loads and it will still work.
Is there a file size or quantity limit?
Technically, there's a ceiling of around 50MB per file because browsers limit in-memory image processing. For practical use, you can compress as many images as your device can hold in RAM — typically dozens to hundreds at once on a modern laptop.
Will compression reduce my image quality?
A little, but usually not visibly. At the default 75% quality setting, most people cannot tell the difference between the original and the compressed version, especially on screens. If you need pixel-perfect output — for printing, for example — use PNG output and push quality to 95%.
What happens to transparent PNGs when I convert them to JPEG?
JPEG has no concept of transparency, so transparent areas have to be filled with a solid colour. This tool automatically composites PNG and WebP images onto a white background before writing the JPEG, so you won't see a black block where the transparency used to be.
Can I use this for commercial work?
Yes. There is no licence restriction on what you compress. The tool is free, and the output is yours.
Does it work on phones?
Yes. The interface is responsive and the compression engine works in mobile Safari, Chrome, and Firefox. On phones, very large batches may run slower because of limited memory.