Image Compressor
Shrink a JPG or PNG's file size with an adjustable quality slider.
Reduce an image's file size by re-encoding it at a lower quality or smaller dimensions — you control the tradeoff with a live before/after size comparison, entirely in your browser.
How to compress an image
- Choose a JPG or PNG. You'll see its original file size.
- Pick a maximum width — or keep the original size.
- Move the quality slider and watch the new file size update live.
- Download when the size and look are right.
Why resizing matters most
File size depends mostly on the number of pixels. A typical 12-megapixel phone photo is 4,000 × 3,000 pixels. Resizing it to 1,600 pixels wide (1,600 × 1,200) keeps only 16% of the pixels — usually a far bigger saving than lowering the quality. Most screens show images well under 2,000 pixels wide, so the extra pixels are wasted on websites and email.
Recommended settings
| Use | Max width | Quality |
|---|---|---|
| Website or blog images | 1200–1600 px | 70–80% |
| Email attachments | 1600 px | 70% |
| Online forms with a size limit | 1200 px | 60–70% |
| Keeping a high-quality copy | Original size | 85–95% |
At around 70–80% quality, most people can't see a difference from the original. Below about 50%, you may start to notice blocky patches in smooth areas like skies.
Why smaller images help
- Faster websites: images are usually the heaviest part of a web page, and slow pages lose visitors.
- Under the limit: job portals, visa forms and school sites often cap uploads at 1–2 MB.
- Email: several full-size phone photos can easily go over a 20–25 MB attachment limit.
Frequently asked questions
Is my image uploaded anywhere?
No — the compression happens entirely in your browser by redrawing the image at a lower quality setting. The file never leaves your device.
Why does the output say JPG even if I uploaded a PNG?
PNG is a lossless format that doesn't have an adjustable "quality" the way JPG does, so meaningful file-size reduction for photos means re-encoding as JPG. If you need to keep transparency, this tool isn't the right fit.
What does the "max width" setting do?
It resizes the image down to that width (keeping its proportions) before compressing — shrinking dimensions is often the biggest single factor in file size, on top of the quality setting.
What happens to transparent areas in a PNG?
The compressed image is saved as a JPG, which can't store transparency, so transparent areas are filled with white. If you need to keep a transparent background, keep the original PNG.
Is the original image changed?
No. Your original file stays exactly as it was. The compressor creates a new, smaller copy for you to download.