Image Compressor

How to use the Image Compressor

1. Select Choose images or drag photos onto the box. You can add up to 30 at once.
2. Pick an output format. JPEG suits photographs, WebP gives smaller files with the same quality in all current browsers, and PNG is lossless for graphics with sharp edges.
3. Set the quality. Around 70–80% is usually indistinguishable from the original for photos while saving a large share of the file size.
4. If the images are larger than they will be displayed, choose a maximum width. Reducing dimensions saves far more than quality alone.
5. Select Compress images, compare the before and after previews, and download files individually or all together as a ZIP.

Example: preparing phone photos for a blog

A 12-megapixel phone photo (4000 × 3000 pixels) saved as a 4.1 MB JPEG is far larger than a blog needs. Compressing it with these settings:

• Format: WebP
• Quality: 75%
• Maximum width: 1920 px

typically produces a file of a few hundred kilobytes — commonly a reduction of over 90% — with no visible difference at normal viewing size. The exact result depends on the photo: detailed scenes like foliage compress less than plain skies.

Why image size matters

Images are usually the heaviest part of a web page. Large images slow down loading, especially on mobile connections, and page speed affects both visitor satisfaction and Core Web Vitals such as Largest Contentful Paint. Outside the web, many email services, forms and messaging apps reject attachments above a certain size.

Most photos straight from a camera or phone are saved with more data than the eye can see at typical viewing sizes. Compression removes that excess.

How compression works here

Each image is decoded by your browser and drawn onto an off-screen canvas, resized if you chose a maximum width. The canvas is then re-encoded with the browser’s built-in JPEG, WebP or PNG encoder at the quality you selected.

• JPEG and WebP are lossy: lower quality removes fine detail the eye is less sensitive to, producing much smaller files. WebP generally reaches the same visual quality at a smaller size than JPEG.
• PNG is lossless, so the quality slider does not apply. Re-saving a PNG rarely shrinks it much; for photos saved as PNG, converting to WebP or JPEG gives the largest saving.

Transparent areas are preserved in WebP and PNG. JPEG has no transparency, so transparent pixels are filled with white. If a compressed file comes out larger than the original — which can happen with images that were already well optimised — the tool tells you and lets you keep the original.

A note on photo metadata

Re-encoding through a canvas does not copy metadata such as EXIF camera details, GPS location and timestamps into the new file. That reduces size and is often a privacy benefit before publishing photos online, but it also means embedded colour profiles and copyright fields are not carried over. The image is displayed the right way up, because browsers apply the EXIF orientation when decoding.

Limitations to keep in mind

• Results depend on your browser’s encoders. Chrome, Edge, Firefox and Safari all support JPEG, PNG and WebP output in current versions; very old browsers may not support WebP.
• Animated GIFs are converted using their first frame only.
• Metadata (EXIF, GPS, colour profiles) is not kept in the compressed file.
• Each image can be up to 25 MB, and very high-resolution images may exceed your device’s memory, particularly on phones.

How your data is handled

Images are read with the browser’s File API and compressed on your device. No image data is uploaded, and nothing is kept once you close the page. You can verify this in your browser’s developer tools: the Network tab shows no upload requests while the tool runs.

Frequently asked questions