Image Compressor

How this image compressor works

The tool decodes each image in your browser, optionally scales it down, and re-encodes it with the HTML5 Canvas encoder at the quality you choose. Three settings control the result:

• Quality (10–100). For JPEG and WebP this sets how aggressively fine detail is discarded. 75 is the default because it is close to what phone cameras and WhatsApp already use; most people cannot tell 75 from 100 on a screen, yet the file is typically 3–5× smaller.
• PNG quality. Below 100, a PNG is reduced to a 256-colour palette with dithering — the same technique TinyPNG and pngquant use — which typically makes photo-like PNGs 60–80% smaller with no visible change. At 100 the PNG is kept lossless, so a file that is already optimised will not shrink.
• Max width / max height. Leave both empty to keep the original dimensions. Set one or both to shrink the image proportionally so it fits inside that box — the tool never stretches or crops.
• Output format. Auto keeps the input format. Switch to JPEG or WebP when you want the smallest possible photo, or PNG when you need transparency or crisp text.

If the re-encoded file would be larger than the original, the tool keeps your original and says so, so you never end up with a “compressed” file that is bigger.

Which setting matters most?

Pixel count drives file size far more than quality. A 12 MP phone photo is about 4000 × 3000 pixels, yet most screens are 1080–1920 pixels wide and web pages rarely show images wider than 1200 px. Downscaling that photo to 1600 px wide cuts the pixel count by roughly 84% before compression even starts.

Example: a 4.2 MB, 4032 × 3024 JPEG.

Your numbers will differ with image content — a sky and a wall compress much better than foliage or fabric — but the pattern holds.

Hitting a specific size limit

Government portals, job sites and university forms in India often demand photos under 50 KB, 100 KB or 200 KB, and signatures under 20 KB. A reliable routine:

1. Set the max width to the form’s required pixel width (commonly 200–600 px).
2. Start at quality 75 and check the output size shown in the file list.
3. Lower the quality in steps of 10 until you are under the limit. Stop before 40, where artefacts become obvious; reduce dimensions instead.
4. For signatures and scanned documents with plain backgrounds, try PNG output — flat colours can compress smaller losslessly than with JPEG.

Because processing is instant, you can experiment freely; nothing is sent to a server and nothing is stored.

Batch compression tips

• Drop a whole folder’s worth of photos at once. Each file is processed in sequence and gets its own download button; “Download all” saves them one after another. Your browser may ask permission for multiple downloads the first time.
• Keep a copy of the originals if you might need to print them. Compression is one-way: detail removed by JPEG or WebP cannot be recovered.
• Photos from phones carry EXIF orientation tags. The tool applies the rotation before saving, so portrait photos stay portrait in the output.
• WebP is supported by every current browser, but some older desktop software and email clients still cannot open it. Use JPEG when sharing with people whose setup you do not know.

Frequently asked questions