Image Compressor
Shrink image file sizes dramatically without visible quality loss — right in your browser.
Lower quality means smaller files. 70% is a great balance.
Images wider than this are scaled down. Leave high to keep original size.
Drop images here or click to browse
Supports JPG, PNG, WEBP — multiple files at once
All compression happens in your browser. Your images are never uploaded anywhere.
Most images on the web are several times larger than they need to be, and that bloat is the single biggest cause of slow-loading pages. A photo straight from a phone camera can be 4 megabytes; the same photo, compressed properly, looks identical at 400 kilobytes. The reason the smaller file looks the same is that human vision cannot perceive most of the data in a raw image — compression discards exactly the information your eyes were never going to notice. This tool compresses images entirely in your browser, using the same techniques a good image editor does, so nothing you upload ever leaves your device.
How the compressor works
Select an image and choose a quality level, and the tool re-encodes it through your browser's built-in image engine at a smaller size. For photographs it uses lossy compression, which achieves dramatic size reductions by discarding imperceptible detail; you can trade quality against file size with a slider and see the result immediately. Everything runs locally through the Canvas API — the image is processed on your machine and never uploaded to any server.
Lossy vs lossless, and when to use each
Lossy (JPG, WebP):
discards data your eye won't miss
→ 70-90% smaller, best for photos
→ quality 80 is the usual sweet spot
Lossless (PNG):
perfect reconstruction, no data lost
→ best for logos, text, sharp edges
→ larger files, but pixel-exact
Reduction ≈ 1 − (compressed size ÷ original size)The key decision is lossy versus lossless, and it maps to content type. Photographs have smooth gradients and no hard edges, so lossy compression at quality 80 typically cuts 80% of the file size with no visible difference — the discarded data was genuinely invisible. Logos, screenshots, and anything with text or sharp lines are different: lossy compression introduces ugly halos around edges, so those belong in lossless PNG. Choosing the wrong one is why a compressed logo looks fuzzy or a compressed photo is needlessly huge.
What to know about image compression
- 1Quality 80 is the sweet spot for photos. Below about 75 you start to see compression artifacts — blocky patches and haloing — while above 85 the file grows fast for gains no one can perceive. Most of the time, 80 delivers a file a fraction of the original size that is visually indistinguishable from it.
- 2Resize before you compress; it is the bigger lever. A 4000-pixel-wide photo displayed in a 800-pixel column is wasting 96% of its pixels. Scaling the actual dimensions down to what will be displayed cuts far more file size than quality settings alone, and it should be the first step, not an afterthought.
- 3Match the format to the content. Photos belong in JPG or WebP; logos, icons, and screenshots with text belong in PNG; anything needing transparency needs PNG or WebP, not JPG. The most common compression mistake is using one format for everything — a PNG photo is bloated, a JPG logo is fuzzy.
- 4WebP beats both JPG and PNG on size in modern browsers. It compresses photos smaller than JPG at the same quality and supports transparency like PNG, and every current browser handles it. Unless you must support very old software, WebP is usually the better target for web images.
- 5Compression is generational — never re-compress a compressed file repeatedly. Each lossy save discards more data, so editing and re-saving a JPG several times visibly degrades it. Keep an original or a lossless master, and compress from that each time, rather than compressing an already-compressed copy.
Frequently asked questions
Will compression visibly reduce my image quality?
At sensible settings, no. Lossy compression discards data your eye cannot perceive, so a photo saved at quality 80 typically looks identical to the original while being a fraction of the size. Quality only becomes visible if you push the setting too low, where blocky artifacts appear, or if you compress the wrong kind of image — a logo or text screenshot, which needs lossless PNG instead. Match the method to the content and the loss stays invisible.
Is my image uploaded to a server?
No. Compression runs entirely in your browser using the Canvas API, so the image is processed on your own device and never transmitted or stored anywhere. You can verify this by disconnecting from the internet — the tool keeps working, because there is no server involved. This matters for private photos, documents, or anything you would not want leaving your machine.
What is the difference between JPG, PNG, and WebP?
JPG uses lossy compression ideal for photographs but poor for sharp edges and text, and it cannot do transparency. PNG is lossless, perfect for logos, screenshots, and images needing transparency, but produces larger files for photos. WebP is a modern format that compresses better than both and supports transparency, and it works in every current browser. The rule of thumb: photos to JPG or WebP, graphics with text or transparency to PNG or WebP.
Should I resize or compress to reduce file size?
Both, and resize first. Reducing the pixel dimensions to what will actually be displayed is the larger lever — a 4000-pixel photo shown at 800 pixels is carrying 25 times more pixels than it needs. After resizing to the display size, compressing the smaller image squeezes out the rest. Compression alone on an oversized image leaves most of the potential savings on the table.
Why does my compressed image sometimes look worse than expected?
Usually one of three causes: the quality setting was pushed too low and introduced visible artifacts; the wrong format was used, such as lossy JPG on a logo, which halos the edges; or the file was already compressed and re-compressing degraded it further. Start from an original or lossless master, pick the format that matches the content, and keep quality around 80, and the result will look clean.