How the Compression Works
Each format gets the treatment that actually shrinks it. JPG and WebP are re-encoded at the strength you pick; 70 is a sane default and 85 is hard to tell from the original. PNG is different: re-saving one changes little, so this tool does what the classic PNG compressors do and quantizes the palette, describing the image with a few hundred well-chosen colors instead of millions. On screenshots, flat-color graphics, and logos that routinely cuts the file by half or more with barely visible change.
The slider controls how aggressive the palette gets for PNGs and the encoder quality for JPG and WebP. The readout on every result shows exactly what you saved, so you can push the slider down until the trade stops being worth it.
What to expect by content type
| Content | Typical result |
|---|---|
| Screenshot or UI graphic (PNG) | 40 to 70 percent smaller |
| Photo saved as PNG | Big savings, but converting to WebP is bigger |
| Camera photo (JPG) | 20 to 60 percent depending on the strength |
| Already-optimized files | Little change; the readout will say so honestly |
Photographs that don't need to stay PNG will always shrink further as WebP, and if the image is bigger in pixels than the layout needs, the resizer is the first stop, not the last.