Private browser tool
Image Optimization Lab
Compare the same image as JPG, PNG and WebP. See real file size, dimensions, encoder quality and savings before choosing a format.
The image never leaves your device.
Choose one image
JPG, PNG, WebP or HEIC. Processed locally in your browser.
Set a comparable quality
PNG is exported losslessly; this control only applies to JPG and WebP. Every variant keeps the original dimensions.
Same file, same pixels and your browser's real encoder. Results can vary slightly between devices.
Choose an image format from evidence, not guesswork
Changing an image format can make a dramatic difference, but there is no universal winner. Photographs, screenshots, transparent graphics and illustrations respond differently to JPG, PNG and WebP encoding.
The lab exports all three versions from the same source pixels without resizing. JPG and WebP use the quality level you choose, while PNG remains a lossless browser export. That makes file size, dimensions and encoding settings visible in one comparison.
The recommendation identifies the smallest result from this specific test. It does not pretend that file size is the only concern: the previews, transparency requirements, browser compatibility and final use should still guide your choice.
What each format is usually good at
- JPG for widely compatible photographs and email attachments
- PNG for transparency, interface graphics and lossless export
- WebP for modern websites, product images and lighter downloads
- A lower quality setting for smaller files when slight detail loss is acceptable
- A higher quality setting when fine texture and gradients matter
Image optimization lab FAQ
Does the lab upload my image?
No. The comparison and downloads are created locally by your browser.
Is the quality percentage a visual quality score?
No. It is the quality setting passed to the browser's JPG and WebP encoder. PNG is exported without that lossy quality setting.
Why can PNG become larger than the original?
PNG is lossless and browser re-encoding can produce a larger file, especially for photographs. It is often more useful for transparency and crisp graphics.
Why can results vary between browsers?
Browsers and operating systems can use different image encoders. The lab reports the actual files produced on your current device.
Does the recommendation always mean best quality?
No. It identifies the smallest tested file. Review the preview and choose based on appearance, compatibility, transparency and final use.