Big image files slow down websites, bounce off email attachment limits and eat storage. Compressing them fixes all three — and done right, nobody can tell the difference.
Why images get so big
A photo straight from a phone camera can be 4–12 MB. Most of that detail is invisible once the image is displayed at normal size on a screen. Compression removes that redundant data so the file drops to a fraction of its size while looking the same.
Lossy vs lossless — the important bit
- Lossy compression (JPG, WebP) discards fine detail to get dramatically smaller files. The trick is choosing a level where the loss is invisible.
- Lossless compression (PNG) keeps every pixel but saves less space.
For photos, lossy at a medium–high quality setting is the sweet spot: often 60–80% smaller with no noticeable change.
How to compress an image
- Open Compress Image.
- Drop in your JPG, PNG or WebP.
- Pick a quality level — Medium is the recommended balance.
- Download the smaller file.
Everything runs in your browser, so even large photos are processed on your device without uploading.
Extra ways to shrink a file
- Resize it. If an image is 4000px wide but will only ever display at 1200px, resize it first — that alone can cut the size by 80%.
- Switch to WebP. Converting to WebP usually beats JPG at the same quality.
- Choose the right format. A screenshot saved as PNG is often smaller and sharper than as JPG; a photo is the opposite.
A good target
For web use, aim for photos under 200–300 KB and thumbnails under 50 KB. Hit that and your pages will feel noticeably faster — which also helps your search ranking.