Compress images to any size, in your browser
Shrink JPG, PNG, WebP and HEIC photos by up to 90% with barely visible quality loss. Set a target size (for example 100 KB for a form upload) and the tool finds the best quality that fits. Up to 200 images at once, nothing uploaded.
How to use the Image Compressor
- Drop one or many images, or paste a screenshot with Ctrl+V.
- Pick a target size (for example “Under 100 KB”) or set the quality slider.
- Optionally limit the width — a 4000 px phone photo rarely needs to stay 4000 px.
- Click Compress. Download each file or all of them as a ZIP.
How image compression works here
JPEG and WebP are lossy formats: the encoder keeps the detail your eye notices and throws away what it does not. The quality setting (0–100) controls how aggressive that is. Most photos look identical at quality 80 and are 40–60% smaller than the camera original; at 60 they are still fine for the web and often 80% smaller. This tool re-encodes your image on your device using the browser's own encoder, so there is no upload and no waiting.
When you choose a target size, the tool runs a binary search over the quality value: it encodes at 50%, checks the size, moves up or down, and repeats eight times to land on the highest quality that still fits under your limit. That is how you get an image under 100 KB without guessing.
PNG, screenshots and transparency
PNG is lossless, so "quality" does not apply. Compressing a PNG here re-encodes it and strips metadata; savings are modest unless you also reduce the dimensions. If the PNG is a photo rather than a graphic, convert it to JPG or WebP for a 5–10× reduction. Transparency is preserved when the output is PNG or WebP; JPG has no alpha channel, so transparent areas become white.
When to downscale instead
File size grows with pixel count. A 12-megapixel photo at 4032 × 3024 px is far larger than anything a website, email or form needs. Setting a max width of 1920 px (or 1080 px for social media) usually cuts size more than any quality change, with no visible loss on a screen.
Typical results
| Input | Setting | Result |
|---|---|---|
| iPhone photo, 3.8 MB HEIC | Under 500 KB, max 1920 px | ≈ 380 KB JPG |
| Screenshot, 1.2 MB PNG | WebP, quality 80 | ≈ 140 KB |
| DSLR JPG, 9 MB | Quality 75 | ≈ 2.1 MB |
Results depend on the image content: noisy photos compress less than clean graphics.
Frequently asked questions
Does compressing reduce image quality?
Slightly, for JPG and WebP. At quality 75–85 the difference is invisible on screens. Use PNG output if you need pixel-perfect results.
Is there a file size or count limit?
No hard limit. Because processing happens on your device, the only limit is your browser memory; 200 files of 10 MB each is fine on a normal laptop.
Are my images uploaded anywhere?
No. The tool runs entirely in your browser. You can switch off Wi-Fi after the page loads and it still works.
Why is my compressed file bigger than the original?
It happens with already-optimised images. In that case the tool returns your original untouched so you never lose bytes.
Can I compress HEIC photos from an iPhone?
Yes. HEIC files are decoded on your device and saved as JPG or WebP, which every website accepts.
Privacy
This tool runs entirely inside your browser using WebAssembly and the Canvas/File APIs. Your files are never uploaded to ToolFlint or any third party; you can verify this in your browser's network tab or by switching to airplane mode after the page loads. Read how we process files.
Last updated 2026-09-23.