How to reduce image file size
Three things decide how big an image file is: the number of pixels, the format and the compression level. Change the right one and a 5 MB photo becomes 200 KB.
Open the tool: Image Compressor
1. Resolution: the biggest lever
A 12-megapixel phone photo is about 4000 × 3000 pixels. Most screens show an image no wider than 1600-2000 pixels, so the rest is wasted. Halving the width and height leaves a quarter of the pixels and roughly a quarter of the file size.
2. Quality: where the eye stops noticing
- 90-100: nearly identical to the original, large files.
- 75-85: the usual choice for photos on websites.
- 50-70: small files, fine for thumbnails and previews.
- Below 50: visible blocks, blurry text and banding.
3. Format: pick the one that fits the content
| Content | Best format | Why |
|---|---|---|
| Photos | WebP or JPG | Lossy compression is made for smooth colour changes |
| Screenshots, text, charts | PNG (palette) or WebP | Sharp edges stay clean |
| Logos with transparency | PNG or WebP | JPG cannot store transparency |
4. Metadata
Photos carry EXIF data such as the camera model, date and often the GPS position. It is usually only a few KB, but it can reveal where a photo was taken. A compressed file from this tool contains no EXIF data.
Common size limits
- Many job portals and government forms: 50-200 KB for photos and signatures.
- Email: keep the whole message under 10-20 MB, so about 300 KB per photo.
- Web pages: aim for under 200 KB for most images and under 500 KB for large hero photos.