Compress Image

How to use: step by step

1. 1
   Drop or select your image
   Drag an image onto the upload area or click to browse. JPEG, PNG, WebP and BMP are all accepted.
2. 2
   Choose output format
   Pick JPEG, WebP or PNG (lossless). WebP gives the best compression-to-quality ratio for most photos.
3. 3
   Drag the quality slider
   Move the slider between 10% (smallest file) and 100% (no loss). Compression fires automatically.
4. 4
   Compare before and after
   The side-by-side preview shows original size vs compressed size so you can judge the trade-off visually.
5. 5
   Download the result
   Click Download to save the compressed image. The file is generated entirely in your browser.

Frequently Asked Questions

Will compressing an image reduce its resolution?

No. This tool only reduces the file size through lossy or lossless encoding. The pixel dimensions (width × height) remain exactly the same as the original.

Which quality setting should I use for web images?

For JPEG and WebP, 70–80% is the sweet spot for most photographs: significant file size reduction with no visually noticeable quality loss at normal viewing sizes.

Does the tool upload my images to a server?

No. Compression is done entirely in your browser using the HTML Canvas API and the browser's built-in image encoder. Your files never leave your device.

Why does PNG compression show 0% savings?

PNG uses lossless compression, so the Canvas API re-encodes at full quality. For PNG the tool ensures a clean re-encode; for significant size reduction choose JPEG or WebP instead.

What is the maximum file size I can compress?

There is no server-side limit because processing happens in your browser. Very large images (above ~50 MB) may be slow depending on your device's RAM and CPU.

Can I compress multiple images at once?

The compressor processes one image at a time with a quality preview. For batch conversion of multiple files use the Format Converter tool which supports batch input.

What is the difference between JPEG and WebP compression?

WebP typically produces files 25–35% smaller than JPEG at equivalent perceptual quality, and it also supports transparency. Use WebP for web images if your audience uses modern browsers.

Is it free to use with no limits?

Yes. AlteredIdea is completely free, requires no account, and places no limit on the number of images you compress.

How do I compress an image for email without losing quality?

Select WebP or JPEG output and set the quality slider to 75-85%. This typically reduces file size by 50-70% while keeping the image sharp enough for email. Most email clients support both formats. Aim for a final size below 500 KB for fast loading in any inbox.

Will compressing an image for my website improve page speed?

Yes, significantly. Image file size is one of the biggest contributors to slow page load times. Compressing images to WebP at 80% quality can reduce your total page weight by 30-60%, which directly improves Google PageSpeed score and Core Web Vitals metrics.