How to compress images
Add your images
Drop in JPG, PNG or WebP files (HEIC and AVIF become JPG). Any number at once.
Adjust if you like
Quality 75 is a strong default for photos. For PNG, colour reduction gives the biggest savings.
Download
Every file keeps its format and name. Get them one by one or as a ZIP.
Compression without the upload
Popular compressors upload your files, process them on their servers and limit how many you can do for free. KeepPixels runs the same kind of professional encoders – MozJPEG, oxipng and libwebp – directly in your browser, with no upload and no quota.
How each format is compressed
KeepPixels picks the right tool for each format and keeps the format you started with.
JPG: MozJPEG
MozJPEG is an encoder from Mozilla that produces smaller JPGs than standard encoders at the same visual quality. The quality slider controls the trade-off; 75 is a good balance for photos on screen, 85–90 for printing.
PNG: colour reduction and oxipng
Screenshots, logos and graphics rarely need millions of colours. Reducing them to a well-chosen palette of 256 colours usually cuts the size by 60–80%, then oxipng repacks the file losslessly. Turn colour reduction off for photos saved as PNG – oxipng alone still trims the file without changing a single pixel.
WebP: libwebp
WebP files are re-encoded with Google’s libwebp at the quality you choose.
Which tool do you need?
- Fixed limit on a form? Use compress to an exact size.
- Image too large in pixels? Use resize images.
Learn more
- How to reduce an image's file size without ruining itA form says "max 200 KB" and your photo is 4 MB? What makes images big, the right order of steps, and the sizes that work for common uploads.
- What is a HEIC file?HEIC is the photo format iPhones use by default. What it is, why Apple chose it, which devices open it, and how to turn it into a JPG when you need one.
- HEIC vs JPG – which is better?HEIC saves space, JPG opens everywhere. A clear comparison of quality, file size, colour and compatibility, and when to use which.
- How to open HEIC files on WindowsWindows can't open iPhone HEIC photos out of the box. Four ways to view them – with Microsoft's extensions, free viewers or by converting to JPG.
- How to make your iPhone save photos as JPGThree ways to get JPGs from an iPhone – change the camera format, convert during transfer, or convert only the photos you share.
Frequently asked questions
How much smaller will my files get?
Photos straight from a phone or camera often shrink by 50–80% at quality 75. Images that were already optimised for the web shrink less – and if a file can't be made smaller, KeepPixels keeps your original.
Will people see a difference?
At quality 75 most people can't tell the compressed photo from the original at normal viewing size. Move the slider up if you see artefacts in fine details.
What's the difference between compressing and resizing?
Compressing keeps the width and height and stores the pixels more efficiently. Resizing reduces the number of pixels. For the smallest files, do both – or use compress to an exact size.
Is transparency kept in PNG files?
Yes, including semi-transparent edges. Colour reduction works with transparency too.
Why does a reduced-colour PNG show bands in gradients?
Colour reduction limits a PNG to 256 colours, which is perfect for screenshots and graphics but can create banding in photos. Untick the option to compress PNG photos losslessly.
Are my files uploaded?
No. All compression runs on your device.