Reduce file size while keeping high quality
Use high quality mode to reduce size and compare against the source. Identical pixels are not guaranteed.
High quality is the default mode, automatically searching quality to limit visible differences. This page starts with high quality mode and the original format. For JPG, WebP, and AVIF, the search aims for an SSIM of at least 0.985.
SSIM is calculated on comparison images with a longest side of up to 512 pixels. A notice appears if the threshold is missed, and reaching it does not mean every pixel is identical. PNG input also receives a separate lossless optimization result.
With original format selected, if dimensions and refinements are unchanged and the encoded result is not smaller, the source file is kept. Its metadata remains in that case. Re-encoded files do not retain the original EXIF metadata, including location information.
How to use
- Select the original photo.
- Start with high quality mode and the original format.
- Check the comparison, SSIM notice, and actual file size, then download.
Tip
High quality does not mean lossless. For PNG pixels that must be preserved, check the lossless result without resizing or refinements.
Frequently asked questions
Does this mean exactly the same quality?
No. For lossy formats, the search aims for an SSIM of at least 0.985. It does not guarantee identical pixels, so compare the result yourself.
Why do I get the original file back?
With original format selected, the source is used when dimensions and refinements are unchanged and the result is not smaller. Original metadata also remains in this case.
Does automatic format include AVIF?
No. Automatic compares JPG and WebP, or PNG and WebP for transparent images. Select AVIF explicitly using the format option or the extra result button.
Are iPhone HEIC/HEIF photos supported?
Yes. The first image in a HEIC/HEIF file is decoded in your browser. Keep original format saves it as JPG. If decoding fails, convert the photo to JPG and try again.